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Extraction of transient signal from GPS position time series by employing ICA

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Geodesy and Geodynamics 2023年第6期14卷 597-604页

作者： Shangwu Song Ming Hao yuhang li Qingliang Wang The Second Monitoring and Application Center China Earthquake AdministrationXi'an 710043China

Transient deformation,such as post-seismic slip,slow slip and pre-seismic slip events,is a limited lowfrequency deformation that can last for hours to months,in contrast to a sudden slip on a fault caused by *** Global Positioning System(CGPS),one of the most common geodetic techniques for continuously monitoring crustal deformation,is capable of capturing transient deformation signals.A critical point in characterizing transient deformation signals is the development of extracting and deciphering transient deformation signals from a huge and messy data set of position time *** Component Analysis(PCA),one of the data-driven methods,has been employed to derive transient deformation signals from position time series combing with Kalman *** Component Analysis(ICA)performs well in recovering and separating the sources of observed data,however,it is rarely used in extracting transient deformation *** aim to decompose the transient deformation signals from the daily GPS observation deployed in Akutan Island from 2007 to 2015 with the ICA method and obtain the spatiotemporal responses to the source signals of transient *** results indicate that ICA method can also characterize effectively transient deformation signals spatially and ***,the independent relationship between sources obtained by ICA allows for flexibility in linearly combining different sources.

关键词： Transient deformation ICA Kalman filter GPS time series Akutan

Analytical transient phase change heat transfer model of wearable electronics with a thermal protection substrate

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Applied Mathematics and Mechanics(English Edition) 2020年第11期41卷 1599-1610页

作者： Yingli SHI Junyun JI Yafei YIN yuhang li Yufeng XING Institute of Solid Mechanics Beihang UniversityBeijing 100191China BOE Technology Group Company limited Beijing 100176China University Electronic Science and Technology China State Key Laboratory of Electronic Thin Films and Integrated DeviceChengdu 610054China Institute of Structure and Environment Engineering Beijing 100076China State Key Laboratory of Structural Analysis for Industrial Equipment Dalian University of TechnologyDalian 116024Liaoning ProvinceChina

As thermal protection substrates for wearable electronics,functional soft composites made of polymer materials embedded with phase change materials and metal layers demonstrate unique capabilities for the thermal protection of human ***,we develop an analytical transient phase change heat transfer model to investigate the thermal performance of a wearable electronic device with a thermal protection *** model is validated by experiments and the finite element analysis(FEA).The effects of the substrate structure size and heat source power input on the temperature management efficiency are investigated systematically and *** results show that the objective of thermal management for wearable electronics is achieved by the following thermal protection *** metal thin film helps to dissipate heat along the in-plane direction by reconfiguring the direction of heat flow,while the phase change material assimilates excessive *** results will not only promote the fundamental understanding of the thermal properties of wearable electronics incorporating thermal protection substrates,but also facilitate the rational design of thermal protection substrates for wearable electronics.

关键词： wearable electronics functional composite theoretical heat transfer analysis thermal management

All-optical complex field imaging using diffractive processors

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light(Science & Applications) 2024年第6期13卷 1122-1139页

作者： Jingxi li yuhang li Tianyi Gan Che-Yung Shen Mona Jarrahi Aydogan Ozcan Electrical and Computer Engineering Department University of CaliforniaLos AngelesCA90095USA Bioengineering Department University of CaliforniaLos AngelesCA90095USA California NanoSystems Institute(CNSI) University of CaliforniaLos AngelesCA90095USA

Complex field imaging,which captures both the amplitude and phase information of input optical fields or objects,can offer rich structural insights into samples,such as their absorption and refractive index ***,conventional image sensors are intensity-based and inherently lack the capability to directly measure the phase distribution of a *** limitation can be overcome using interferometric or holographic methods,often supplemented by iterative phase retrieval algorithms,leading to a considerable increase in hardware complexity and computational ***,we present a complex field imager design that enables snapshot imaging of both the amplitude and quantitative phase information of input fields using an intensity-based sensor array without any digital *** design utilizes successive deep learning-optimized diffractive surfaces that are structured to collectively modulate the input complex field,forming two independent imaging channels that perform amplitude-to-amplitude and phase-to-intensity transformations between the input and output planes within a compact optical design,axially spanning~100 *** intensity distributions of the output fields at these two channels on the sensor plane directly correspond to the amplitude and quantitative phase profiles of the input complex field,eliminating the need for any digital image reconstruction *** experimentally validated the efficacy of our complex field diffractive imager designs through 3D-printed prototypes operating at the terahertz spectrum,with the output amplitude and phase channel images closely aligning with our numerical *** envision that this complex field imager will have various applications in security,biomedical imaging,sensing and material science,among others.

关键词： field. utilize collective

Sequential vigilance is unpredictable in reproductive Black-necked Cranes

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Avian Research 2019年第1期10卷 82-88页

作者： yuhang li Le Yang Yunchao Luo Yiqian Wu Zhongqiu li School of life Sciences Nanjing University Tibet Plateau Institute of Biology

Background:Vigilance refers to the behavior of animals scanning their surroundings with a main purpose of *** vigilance can serve the function of anti-predation depends on its unpredictability,meaning instantaneous randomness,sequential randomness,and independence,the three assumptions from Pulliam model(J Theor Biol 38:419,1973).Here we tested two of these three assumptions in reproductive Black-necked Cranes(Grus nigricollis) in Tibetan Plateau:instantaneous randomness and sequential ***:Observations were carried out in July and September of 2014,July and August in 2017 in Selincuo National Nature Reserve,Tibet,with the help of focal sampling *** instantaneous randomness,we used Kolmogorov–Smirnov test for its negative exponential distribution;for sequential randomness,we used Run test,correlation analysis,and generalized linear model to see if an inter-scan and its previous scan were ***:Not similar to some recent studies,we did not find a significant predictable vigilance in this *** inter-scan intervals(86/100,86.0%) passed negative exponential distribution test,meaning vigilance sequences with instantaneous randomness;most inter-scan intervals(91/100,91.0%) passed sequential random test,showing vigilance sequences were random ***:Our results suggest that keeping a vigilance pattern with unpredictability is beneficial to the survival of the Black-necked Cranes,which are facing with both cruel natural environments and high predation risks.

关键词： Black-necked Cranes Instantaneous randomness Sequential randomness

All-optical image classification through unknown random diffusers using a single-pixel diffractive network

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light(Science & Applications) 2023年第4期12卷 570-584页

作者： Bijie Bai yuhang li Yi Luo Xurong li Ege Cetintas Mona Jarrrahi Aydogan Ozcan Electrical and Computer Engineering Department University of CaliforniaLos AngelesCalifornia 90095USA Bioengineering Department University of CaliforniaLos AngelesCalifornia 90095USA California Nano Systems Institute(CNSI) University of CaliforniaLos AngelesCalifornia 90095USA

Classification of an object behind a random and unknown scattering medium sets a challenging task for computational imaging and machine vision *** deep learning-based approaches demonstrated the classification of objects using diffuser-distorted patterns collected by an image *** methods demand relatively large-scale computing using deep neural networks running on digital ***,we present an all-optical processor to directly classify unknown objects through unknown,random phase diffusers using broadband illumination detected with a single pixel.A set of transmissive diffractive layers,optimized using deep learning,forms a physical network that all-optically maps the spatial information of an input object behind a random diffuser into the power spectrum of the output light detected through a single pixel at the output plane of the diffractive *** numerically demonstrated the accuracy of this framework using broadband radiation to classify unknown handwritten digits through random new diffusers,never used during the training phase,and achieved a blind testing accuracy of 87.74±1.12%.We also experimentally validated our single-pixel broadband diffractive network by classifying handwritten digits"0"and"1"through a random diffuser using terahertz waves and a 3D-printed diffractive *** single-pixel all-optical object classification system through random diffusers is based on passive diffractive layers that process broadband input light and can operate at any part of the electromagnetic spectrum by simply scaling the diffractive features proportional to the wavelength range of *** results have various potential applications in,e.g.,biomedical imaging,security,robotics,and autonomous driving.

关键词： network processor random

The morphological and phylogenetic characterization for the dinoflagellate Margalefidinium fulvescens (=Cochlodinium fulvescens) isolated from the Jiaozhou Bay, China

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Acta Oceanologica Sinica 2018年第10期37卷 11-17页

作者： HU Zhangxi DENG Yunyan li yuhang TANG Ying Zhong CAS Key Laboratory of Marine Ecology and Environmental Sciences Institute of OceanologyChinese Academy of SciencesQingdao 266071China Laboratory for Marine Ecology and Environmental Science Pilot National Laboratory for Marine Science and Technology(Qingdao)Qingdao 266237China Center for Ocean Mega-Science Chinese Academy of SciencesQingdao 266071China Department of Marine Organism Taxonomy and Phylogeny Institute of OceanologyChinese Academy of SciencesQingdao 266071China

The dinoflagellate genus Margalefidinium has been split from Cochlodinium as a new genus recently and Margalefidiniumfulvescens is one of the five Margalefidinium species. Margalefidiniumfulvescens is toxic and has been reported from the coastal waters of USA, Canada, Mexico, China, Japan, Indonesia, Korea, Pakistan and Spain. Here we provide the morphological and phylogenetic characterization for an isolate of it from the Jiaozhou Bay, Qingdao, China. Our results showed that the vegetative cells were subspherical to ellipsoidal, 34-60 pm in length, and 19-41 pm in width. Both single cell forms and colonies in chains of 2, 4, or 8 cells were observed in cultures, but chain forms with 2 or 4 cells were observed more often in the field samples. The cingulum was rather deep, encircling the cell approximately twice, but the sulcus was rather narrow, surrounding the cell about one turn. The nucleus was spherical and located at the central epicone. The chloroplasts were granular, brownish, and scattered peripherally. An orange pigmented body also appeared in the epicone. The apical groove appeared vase-like as previously described. Under epi-fluorescence microscopy, a pumpkin-like structure was clearly observed, in which cells were embedded. Cells were observed to exit from the structure, which led us to a hypothesis that the structure may provide cells a shelter to avoid predation or to respond to other stresses. The phylogenetic analyses based on partial LSU rDNA sequences indicated that M. fulvescens from the Jiaozhou Bay was grouped with M. fulvescens populations from other origins and closely related to the clade ofM. polykrikoides. Our morphological observations and phylogenetic analyses together confirmed the presence of M. fulvescens in China and our monitoring has also observed the species dominant in the dinoflagellate community of the Jiaozhou Bay in the early autumn of 2015, which alerted us to continually monitor this bloom-forming species in the region.

关键词： Margalefidiniumfulvescens morphology phylogeny pumpkin-like structure Jiaozhou Bay China

Optimal decomposition level selection approach in wavelet threshold denoising algorithm for ECG signal

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The Journal of China Universities of Posts and Telecommunications 2023年第4期30卷 86-104页

作者： Yao Yindi Yi Jun Zeng Zhibin li Xiong Wang Chen li yuhang School of Communications and Information Engineering Xi'an University of Posts and TelecommunicationsXi'an 710121China School of Microelectronics Xidian UniversityXi'an 710071China School of Information and Communication Engineering Beijing University of Posts and TelecommunicationsBeijing 100876China

The effect of electrocardiogram(ECG)signal wavelet denoising depends on the optimal configuration of its control parameters and the selection of the optimal decomposition ***,the existing optimal decomposition level selection scheme has some problems,such as lack of reliable theoretical guidance and insufficient accuracy,which need to be solved *** solve this problem,this paper proposes an optimal decomposition level selection method based on multi-index fusion,which is used to select the optimal decomposition level for wavelet threshold denoising of ECG *** the stage of index selection,in order to overcome the limitation of a single evaluation index,the optimal multi-evaluation index is selected through the joint analysis of the geometric and physical significance of traditional evaluation *** the stage of index fusion,based on the method of weighting the selected multiple indexes by the information entropy weight method and the coefficient of variation method,an optimal decomposition level selection method based on the evaluation index Z is proposed to improve the accuracy of the optimal decomposition level ***,extensive experiments are carried out on the real ECG signal from the Massachusetts Institute of Technology-Beth Israel Hospital(MIT-BIH)arrhythmia database and simulated signal to test the performance of the proposed *** experimental results show that the accuracy of this method is superior to other related methods,and it can achieve better denoising effect of ECG signal.

关键词： ECG signal wavelet threshold denoising optimal decomposition level muti-index fusion

Electrocatalytic CO_(2) Reduction over Bimetallic Bi-Based Catalysts:A Review

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CCS Chemistry 2023年第3期5卷 544-567页

作者： Wei Chen Yating Wang yuhang li Chunzhong li Key Laboratory for Ultrafine Materials of Ministry of Education Shanghai Engineering Research Center of Hierarchical NanomaterialsFrontiers Science Center for Materiobiology and Dynamic ChemistrySchool of Materials Science and EngineeringEast China University of Science and TechnologyShanghai 200237 School of Chemical Engineering East China University of Science and TechnologyShanghai 200237

Electrocatalytic reduction of carbon dioxide(CO_(2))to valuable fuels is an up-and-coming *** to the low cost,environmental friendliness,and high selectivity to formate single product at low overpotentials,bismuth(Bi)-based catalysts have attracted extensive research *** this review,the reaction mechanisms of Bi-based catalysts are first introduced,and the bimetallic Bi-based catalysts synthesized by alloying,doping,and loading strategies are reviewed from the aspects of catalyst component,morphology,synthesis procedure,and performance optimization for electrocatalytic CO_(2)*** provide an in-depth discussion of the existing challenges and an outlook for this highly promising kind of electrocatalysis.

关键词： bimetallic bi-based catalysts CO_(2)reduction electrocatalysis

Roles of electrolyte additive in Zn chemistry

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Nano Research 2023年第7期16卷 9179-9194页

作者： yuhang li Hong Yao Xiangjie liu Xiaotong Yang Du Yuan College of Materials Science and Engineering Changsha University of Science and TechnologyChangsha 410004China

Electrolyte regulation plays its critical role in addressing the reversibility issue of metallic Zn anode towards high-performance aqueous zinc ion *** view of the flourish electrolyte additive approach,the review is organized to discuss the influence of electrolyte additive on the electrolyte-Zn chemistry for the representative zinc ***,the effects of electrolyte additives on the fundamental physicochemical properties of electrolytes,Zn surface,and Zn deposition are discussed and *** on the revealed roles of additives in interface reaction across current literature,we further provide outlook and perspective on current issues of the additive approach and potential directions.

关键词： electrolyte additive solvation transport interface texture