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Thermogalvanic hydrogel-based e-skin for self-powered on-body dual-modal temperature and strain sensing

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Microsystems & Nanoengineering 2024年第2期10卷 293-302页

作者： Zhaosu Wang Ning Li Xinru Yang Zhiyi Zhang Hulin Zhang Xiaojing Cui college of electronic information and Optical Engineering Taiyuan University of TechnologyTaiyuan030024China college of Materials Science and Engineering Taiyuan University of TechnologyTaiyuan030024China School of physics and information Engineering Shanxi Normal UniversityTaiyuan030031China

Sensing of both temperature and strain is crucial for various diagnostic and therapeutic purposes.Here,we present a novel hydrogel-based electronic skin(e-skin)capable of dual-mode sensing of temperature and strain.The thermocouple ion selected for this study is the iodine/triiodide(I−/I3−)redox couple,which is a common component in everyday disinfectants.By leveraging the thermoelectric conversion in conjunction with the inherent piezoresistive effect of a gel electrolyte,self-powered sensing is achieved by utilizing the temperature difference between the human body and the external environment.The composite hydrogels synthesized from polyvinyl alcohol(PVA)monomers using a simple freeze‒thaw method exhibit remarkable flexibility,extensibility,and adaptability to human tissue.The incorporation of zwitterions further augments the resistance of the hydrogel to dehydration and low temperatures,allowing maintenance of more than 90%of its weight after 48 h in the air.Given its robust thermal current response,the hydrogel was encapsulated and then integrated onto various areas of the human body,including the cheeks,fingers,and elbows.Furthermore,the detection of the head-down state and the monitoring of foot movements demonstrate the promising application of the hydrogel in supervising the neck posture of sedentary office workers and the activity status.The successful demonstration of self-powered on-body temperature and strain sensing opens up new possibilities for wearable intelligent electronics and robotics.

关键词： hydrogel modal utilizing

Poles Extraction Based LiDAR Localization for Autonomous Robot Systems

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Journal of Systems Science & Complexity 2024年第4期37卷 1413-1424页

作者： HONG Xin DONG Yi college of electronic and information Engineering Tongji University

With the development of intelligent technology, the problem of Li DAR-based localization has played an increasingly important role in the localization of robots in unmanned systems. Since the dense point clouds from the environment requires a large amount of memory, specific and stable structural features, such as pole-like objects in the environment, can serve as the ideal landmarks for localization in unmanned systems, which can effectively reduce the memory usage and mitigate the effects of dynamic environment changes. In this paper, the authors propose a pole-like objects extraction approach and then, it is applied into the localization system of mobile robots. Under the same experimental conditions, the proposed method can extract more pole-like objects and achieve better long-term localization accuracy than some existing methods in different urban environmental datasets.

关键词： Pole-like landmark extraction robot localization

Research on visual sensitivity characteristics of amorphous silicon photocells

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Optoelectronics Letters 2024年第7期20卷 385-392页

作者： WANG Yan CAI Nuo ZHOU Xiaodi LU Yabin WANG Chunyan FAN Xinmin Department of physics and electronic information Weifang University Shandong North Optical electronics Co. Ltd.China North Industries Group college of electronic information and Optical Engineering Nankai University

This study delves into the feasibility of using amorphous silicon photocells as photosensitive units for retinal prostheses. Firstly, theoretical simulations coupled with experimental results demonstrated its strong light absorption and quantum efficiency within the 300—800 nm range. Subsequently, measurements on its visual sensitivity properties were conducted. The findings revealed that under photopic vision conditions, the photocells could provide the stimulating current required for the human retinal nerve cells. Finally, the visual spectral sensitivity curve of the amorphous silicon photocells was assessed, and the results indicated that the spectral sensitivity curve of the amorphous silicon photocells closely mirrors the visual function curve of the human eye under photopic conditions, demonstrating a response to light across various wavelengths.

关键词： A

A statistical analysis of the Kappa-type energy spectrum distribution of radiation belt electrons observed by Van Allen Probes

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Earth and Planetary physics 2024年第2期8卷 368-374页

作者： LuHuai Jiao Xin Ma YuanNong Zhang TaiFeng Jin Song Fu BinBin Ni Department of Space physics School of Electronic InformationWuhan UniversityWuhan 430072China

The energy spectrum of energetic electrons is a key factor representing the dynamic variations of Earth’s Van Allen radiation belts.Increased measurements have indicated that the commonly used Maxwellian and Kappa distributions are inadequate for capturing the realistic spectral distributions of radiation belt electrons.Here we adopt the Kappa-type(KT)distribution as the fitting function and perform a statistical analysis to investigate the radiation belt electron flux spectra observed by the Van Allen Probes.By calculating the optimal values of the key KT distribution parameters(i.e.,κandθ2)from the observed spectral shapes,we fit the radiation belt electron fluxes at different L-shells under different geomagnetic conditions.In this manner,we obtain typical values of the KT distribution parameters,which are statistically feasible for modeling the radiation belt electron flux profiles during either geomagnetically quiet or active periods.A comparison of the KT distribution model results with those using the Maxwellian or Kappa distribution reveals the advantage of the KT distribution for studying the overall properties of the radiation belt electron spectral distribution,which has important implications for deepening the current understanding of the radiation belt electron dynamics under evolving geomagnetic conditions.

关键词： radiation belt electron Kappa-type distribution fitting geomagnetic storm

Effect of interplanetary magnetic field B_(x)on the polar electrojets as observed by CHAMP and Swarm satellites

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Earth and Planetary physics 2024年第2期8卷 382-390页

作者： Hui Wang ChengZhi Wang YunFang Zhong Department of Space physics School of Electronic InformationWuhan UniversityWuhan 430072China

Based on 16 years of magnetic field observations from CHAMP and Swarm satellites,this study investigates the influence of the Interplanetary Magnetic Field(IMF)Bx component on the location and peak current density of the polar electrojets(PEJs).We find that the IMF Bx displays obvious local time,seasonal,and hemispherical effects on the PEJs,as follows:(1)Compared to other local times,its influence is weakest at dawn and dusk.(2)In the midnight sectors of both hemispheres,the IMF Bx tends to amplify the westward PEJ when it is0 in the Southern Hemisphere;this effect is relatively stronger in the local winter hemisphere.(3)At noontime,the IMF Bx intensifies the eastward current when it is0,it reduces the westward current;this effect is notably more prominent in the local summer hemisphere.(4)Moreover,the noontime eastward current shifts towards higher latitudes,while the midnight westward current migrates towards lower latitudes when IMF Bx is0 in the Southern Hemisphere.

关键词： polar electrojet interplanetary magnetic field Bx local time asymmetry hemispheric difference

Overshoot phenomena:Observation and simulation

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Earth and Planetary physics 2024年第2期8卷 391-399页

作者： Ting Feng MoRan Liu ShiMin He Xiang Wang Chen Zhou Department of Space physics School of Electronic InformationWuhan UniversityWuhan 430072China

High-power O-mode radio waves can excite artificial instabilities in the F region,according to experiments conducted at the European Incoherent Scatter Science Association(EISCAT)heating facility.The main instabilities include the parametric decay instability(PDI),oscillating two-stream instability(OTSI),and thermal parametric instability(TPI).The PDI and OTSI not only compete with each other,but also compete with the TPI,leading to a two-stage overshoot phenomenon:a miniovershoot occurs on a millisecond time scale after pump-on,followed by the main overshoot.We gain insight into the miniovershoot via a generalized Zakharov model,whereas the main overshoot can be observed as an enhanced plasma line overshoot phenomenon in incoherent scatter radar spectra.We can also observe that the zero-frequency ion line exists only in the initial heating period after a cold start and that the upshifted and downshifted ion lines behave irregularly in the spectra.The simulation results show that competition between the PDI and OTSI leads to an initial peak,which we named the pre-miniovershoot.The following processes,namely ion density caviton generation,and collapse and cascade in the development of the PDI,contribute to the miniovershoot phenomenon.

关键词： overshoot parametric decay instability oscillating two-stream instability competition

Differences between two methods to derive a nonlinear Schrödinger equation and their application scopes

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Chinese physics B 2024年第2期33卷 421-429页

作者：陈羽西张恒段文山 college of physics and electronic Engineering Northwest Normal UniversityLanzhou 730070China

The present paper chooses a dusty plasma as an example to numerically and analytically study the differences between two different methods of obtaining nonlinear Schrödinger equation(NLSE).The first method is to derive a Korteweg–de Vries(KdV)-type equation and then derive the NLSE from the KdV-type equation,while the second one is to directly derive the NLSE from the original equation.It is found that the envelope waves from the two methods have different dispersion relations,different group velocities.The results indicate that two envelope wave solutions from two different methods are completely different.The results also show that the application scope of the envelope wave obtained from the second method is wider than that of the first one,though both methods are valuable in the range of their corresponding application scopes.It is suggested that,for other systems,both methods to derive NLSE may be correct,but their nonlinear wave solutions are different and their application scopes are also different.

关键词： dusty plasmas nonlinear waves particle-in-cell simulation

Triad-displaced ULAs configuration for non-circular sources with larger continuous virtual aperture and enhanced degrees of freedom

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Journal of Systems Engineering and electronics 2024年第1期35卷 81-93页

作者： SHAIKH Abdul Hayee DANG Xiaoyu HUANG Daqing college of electronic and information Engineering Nanjing University of Aeronautics and AstronauticsNanjing 211106China

Non-uniform linear array(NULA)configurations are well renowned due to their structural ability for providing increased degrees of freedom(DOF)and wider array aperture than uniform linear arrays(ULAs).These characteristics play a significant role in improving the direction-of-arrival(DOA)estimation accuracy.However,most of the existing NULA geometries are primarily applicable to circular sources(CSs),while they limitedly improve the DOF and continuous virtual aperture for noncircular sources(NCSs).Toward this purpose,we present a triaddisplaced ULAs(Tdis-ULAs)configuration for NCS.The TdisULAs structure generally consists of three ULAs,which are appropriately placed.The proposed antenna array approach fully exploits the non-circular characteristics of the sources.Given the same number of elements,the Tdis-ULAs design achieves more DOF and larger hole-free co-array aperture than its sparse array competitors.Advantageously,the number of uniform DOF,optimal distribution of elements among the ULAs,and precise element positions are uniquely determined by the closed-form expressions.Moreover,the proposed array also produces a filled resulting co-array.Numerical simulations are conducted to show the performance advantages of the proposed Tdis-ULAs configuration over its counterpart designs.

关键词： direction-of-arrival(DOA)estimation sparse array non-circular source(NCS) sum co-array difference co-array degrees of freedom(DOF)

Acoustic Bilayer Gradient Metasurfaces for Perfect and Asymmetric Beam Splitting

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Chinese physics Letters 2024年第1期41卷 39-50页

作者：权家琪孙宝印伏洋洋高雷徐亚东 Institute of Theoretical and Applied physics School of Physical Science and TechnologySoochow UniversitySuzhou 215006China college of physics Nanjing University of Aeronautics and Astronautics&Key Laboratory of Aerospace Information Materials and Physics(NUAA)MIITNanjing 211106China School of Optical and electronic information Suzhou City UniversitySuzhou 215104China

We experimentally and theoretically present a paradigm for the accurate bilayer design of gradient metasurfaces for wave beam manipulation,producing an extremely asymmetric splitting effect by simply tailoring the interlayer size.This concept arises from anomalous diffraction in phase gradient metasurfaces and the precise combination of the phase gradient in bilayer metasurfaces.Ensured by different diffraction routes in momentum space for incident beams from opposite directions,extremely asymmetric acoustic beam splitting can be generated in a robust way,as demonstrated in experiments through a designed bilayer system.Our work provides a novel approach and feasible platform for designing tunable devices to control wave propagation.

关键词： surfaces splitting asymmetric