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International Conference on advanced Robotics and Mechatronics (ICARM)

作者： You Li Qinlian Yang Peng Fang Rong Song School of Biomedical Engineering Shenzhen Campus of Sun Yat-sen University Shenzhen Guangdong China Guangdong Provincial Key Laboratory of Sensor Technology and Biomedical Instrument Sun Vat-Sen University Guangzhou Guangdong China Research Center for Neural Engineering Shenzhen Institutes of Advanced Technology (SIAT) Chinese Academy of Sciences (CAS) Shenzhen Guangdong China

Functional electrical stimulation (FES) offers an effective approach for foot drop (FD) correction by artificially contracting the tibialis anterior (TA) muscle. The majority of current FES systems employ predetermined stimulation parameters and stimulation profiles, which cannot improve gait performances well considering significant time-variance and individuality of muscle response dynamics under electrical stimulation. To mitigate these challenges, this article proposes a model-based closed-loop control scheme to achieve adaptive adjustment of stimulation intensity profiles using Norm-optimal iterative learning control (NOILC). Firstly, a dynamic model for ankle joint utilizing a Hammerstein structure for subject-specific is developed, as well as the parameters identification. Then, a closed-loop controller based on NOILC is designed to allow tracking of desired trajectory of ankle joint angle for foot drop correction according to FES-induced foot motion. Finally, computer simulation tests are performed and verify that the proposed control method can achieve a good tracking performance through adaptive modulation of stimulation intensity profile, and it is consistent with the physiological characteristics of foot motion.

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Anomalous quantum scattering and transport of electrons with Mexican-hat dispersion induced by electrical potential

arXiv

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arXiv 2024年

作者： Yao, Jiating Zhou, Benliang Zhou, Xiaoying Xiao, Xianbo Zhou, Guanghui Hunan Normal University Changsha410081 China School of Physics and Electronics Hunan Provincial Key Laboratory of Intelligent Sensors Advanced Sensor Materials Hunan University of Science and Technology Xiangtan411201 China School of Computer Science Jiangxi University of Chinese Medicine Nanchang330004 China Department of Physics Shaoyang University Shaoyang422001 China

We theoretically study the quantum scattering and transport of electrons with Mexican-hat dispersion through both step and rectangular potential barriers by using the transfer matrix method. Owing to the torus-like iso-energy lines of the Mexican-hat dispersion, we observe the presence of double reflections and double transmissions in both two different barrier scenarios, i.e., the normal reflection (NR), retro-reflection (RR), normal transmission (NT), and specular transmission (ST). For the step potential with electrons incident from the large wavevector, the transmission is primarily governed by NT with nearly negligible ST, while the reflection is dominant by RR (NR) within (outside) the critical angle. Additionally, for electrons incident from the small wavevector, the NT can be reduced to zero by adjusting the barrier, resulting in a significant enhancement of ST and RR. For the rectangular barrier, the transmission and reflection spectra resemble those of the step barrier, but there are two kinds of resonant tunneling which can lead to perfect NT or ST. There exists a negative differential conductance (NDC) effect in the conductance spectrum. The conductance and the peak-to-valley ratio of the NDC effect can be effectively controlled by adjusting the height and width of the barrier as well as the incident energy. Our results provide a deeper understanding of the electron states governed by the Mexican-hat dispersion. © 2024, CC BY.

关键词： Dispersion (waves)

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Heat distribution of aluminum block with profile for portable thermal cycler calculated using finite element method 5

Heat distribution of aluminum block with profile for portabl...

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5th Asian Conference on Thermoelectrics and the 6th Southeast Asia Conference on Thermoelectrics, ACT and SACT 2020

作者： Sakti, S.P. Abdurrouf Kusuma, F.J. Sensor Technology Laboratory Department of Physics Brawijaya University Jl. Veteran Malang65145 Indonesia Collaborative Research Centre for Advanced Systems and Material Technology Brawijaya University Jl. Veteran Malang65145 Indonesia Computational Physics Laboratory Department of Physics Brawijaya University Jl. Veteran Malang65145 Indonesia

Polymerase Chain Reaction (PCR) becomes one of the essential tools during the COVID pandemic. The heart of the PCR is a thermal cycler. The thermal cycler is a temperature cycle instrument that changes and maintains the vial sample's temperature at a specific target temperature. A simple thermal cycler can be made using thermoelectric as the heater and cooler to control the temperature state. The thermal block temperature distribution is important to make all the vials treated at the same temperature condition. The thermal distribution of an aluminum block as the thermal block for a portable PCR was calculated using the finite element method. The heat source and cooler with a power of 60W were placed at the bottom of the aluminum block. The temperature gradient inside the aluminum body, where the vial was placed, was calculated. The heating and cooling speed were calculated using the model. It was found that the temperature difference between the bottom surface and top surface of the aluminum block is 2.5°C during the transient time. The temperature distribution in a horizontal direction is homogenous, with a temperature difference among the surface being less than 0.01°C. The time required to heating from 24°C to 95°C is 31.05 seconds while cooling from 95°C to 55°C can be reached in 18.05 seconds. © 2021 Institute of Physics Publishing. All rights reserved.

关键词： Finite element method

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Permittivity extraction of glucose solutions through artificial neural networks

Permittivity extraction of glucose solutions through artific...

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Artificial Intelligence and Speech technology (AIST), International Conference on

作者： Syedhassan Alidrus Siti Zuraidah Ibrahim Faridah Hanim Mohd Noh Latifah Munirah Kamarudin Sugchai Tantiviwat Faculty of Electronic Engineering Technology Universiti Malaysia Perlis (UniMAP) Arau Malaysia Centre of Excellence for Advanced Communication Engineering (ACE) Faculty of Electronic Engineering & Technology Universiti Malaysia Perlis (UniMAP) Arau Malaysia Faculty of Engineering Technology Universiti Tun Hussein Onn Malaysia Johor Malaysia Centre of Excellence for Advanced Sensor Technology (CEASTech) Faculty of Electronic Engineering Technology Universiti Malaysia Perlis (UniMAP) Arau Malaysia

This paper presents an Artificial Neural Network (ANN) model to determine the permittivity value of glucose solution at different concentrations predicted using the reflection coefficient value (S11). An open-ended probe connected to a vector network analyzer (VNA) was used to measure the complex permittivity value of glucose solutions at different concentrations. The S11 values and permittivity of these samples were analyzed over a frequency range from 500MHz to 5GHz. 11 glucose solution samples are prepared from 0g/mL to 1g/mL or 0% to 100%. By referring to the difference in frequency, concentration, and dielectric properties, the behavior of the dielectric constant and loss factor are analyzed. To develop the ANN model, 132 data points of S11 values are used as input data and 132 data points of permittivity values are used as target data. To achieve the target accuracy, the model consists of a data set that has unbiased ANN design parameters such as network type as feed-forward back propagation, transfer function as Tan-sigmoid, number of 10 neurons in hidden layer and training algorithm as Levenberg-Marquardt Backpropagation. Validation is carried out through MATLAB software by comparing the measured value and the calculated value, in terms of accuracy the equality of values has reached more than 99% accuracy.

关键词： Backpropagation Training Permittivity measurement Transfer functions Artificial neural networks Mathematical models Data models

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Surface temperature distribution aluminum block with cone tube profile calculated using ANSYS fluent 2

Surface temperature distribution aluminum block with cone tu...

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2nd International Conference on Advances in Physical Sciences and Materials 2021, ICAPSM 2021

作者： Sakti, S.P. Kusuma, F.J. Putro, T. Abdurrouf Sensor Technology Laboratory Department of Physics Brawijaya University Jl. Veteran Malang65145 Indonesia Collaborative Research Centre for Advanced Systems and Material Technology Brawijaya University Jl. Veteran Malang65145 Indonesia Computational Physics Laboratory Department of Physics Brawijaya University Jl. Veteran Malang65145 Indonesia

Thermal Cycler is the main part of the Polymerase Chain Reaction (PCR), which becoming a gold standard for Covid-19 diagnosis. The virus multiplication in an order to a detectable concentration is done by placing the virus solution at a deterministic temperature cycle. The solution is placed in a small tube inserted in a temperature block. Temperature distribution of the thermal block is important to make all the tube with sample treated at the same at desired target temperature. Study on the thermal block made of aluminium 7075 was simulated using fluid dynamic finite element method. Heating and colling to the target temperature was done by providing heat source and heat absorber. The temperature distribution on the surface was mapped. The temperature gradient perpendicular to the heat source was calculated. Assuming the environment of the thermal block was still air, the heating and cooling speed at given heat source and heat removal were calculated using the model. The temperature gradient from the top surface to the bottom surface is less than 2.5?. The temperature difference among point at the surface is less than 0.1?. © Content from this work may be used under the terms of the Creative Commons Attribution 3.0 licence.

关键词： Thermal gradients

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强健超弹的蜘蛛网状聚酰亚胺纤维基导电复合气凝胶用于极端温度下的线性压力传感器

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Science China Materials 2023年第7期66卷 2829-2842页

作者：杨文科刘虎杜厚义张旻悦王春枫尹锐潘曹峰刘春太申长雨 Key Laboratory of Materials Processing and Mold(Zhengzhou University) Ministry of EducationNational Engineering Research Center for Advanced Polymer Processing TechnologyZhengzhou UniversityZhengzhou 450002China CAS Center for Excellence in Nanoscience Beijing Key Laboratory of Micro-nano Energy and SensorBeijing Institute of Nanoenergy and NanosystemsChinese Academy of SciencesBeijing 101400China College of Physics and Optoelectronic Engineering Shenzhen UniversityShenzhen 518060China China Astronaut Research and Training Center Beijing 100094China

压力传感器是人工触觉感应的基石.尽管人们对高性能压力传感器进行了广泛的研究,但解决传感器的高灵敏度、宽线性响应范围和宽工作温度范围仍然面临巨大挑战.在此,我们创新性地应用三乙胺实现了疏水聚酰亚胺纤维(PIFs)在碳纳米管(CNT)... 详细信息

压力传感器是人工触觉感应的基石.尽管人们对高性能压力传感器进行了广泛的研究,但解决传感器的高灵敏度、宽线性响应范围和宽工作温度范围仍然面临巨大挑战.在此,我们创新性地应用三乙胺实现了疏水聚酰亚胺纤维(PIFs)在碳纳米管(CNT)水溶液中的均匀分散,同时纤维的结构不会受到破坏,并利用冻干和热酰亚胺化技术制备了强健超弹的蜘蛛网状(PIF/CNT)导电复合气凝胶.该气凝胶作为压力传感器具有宽线性感应范围(0.01-53.34 kPa)、超低检测限(10 Pa)、高灵敏度(0.507 kPa^(-1))、快速响应/恢复时间(85/80 ms)、稳定的快速压缩响应(500 mm min^(-1))和优异的抗循环疲劳能力(5000次)等优异的传感性能.有限元分析表明,多级纤维网络有利于相邻的导电纤维之间的接触面积在外部压力下有明显的线性变化,使之表现出优异的线性传感性能.该传感器可用于人体生理和运动信号检测、电子皮肤和智能控制,且在极端温度(-100-300℃)下表现出出色的传感稳定性和热绝缘性,可用于极端太空环境下太空服和月球/火星栖息地充气结构的传感单元.本工作为开发下一代线性压力传感器提供了一个简单有效的方法.

关键词： polyimide fibre superelastic aerogel pressure sensor linear sensing environmental tolerance

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Phase-change metasurfaces for reconfigurable image processing

arXiv

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arXiv 2024年

作者： Liu, Tingting Qiu, Jumin Yu, Tianbao Liu, Qiegen Li, Jie Xiao, Shuyuan School of Information Engineering Nanchang University Nanchang330031 China Institute for Advanced Study Nanchang University Nanchang330031 China School of Physics and Materials Science Nanchang University Nanchang330031 China Optoelectronic Sensor Devices and Systems Key Laboratory of Sichuan Provincial University College of Optoelectronic Engineering Chengdu University of Information Technology Chengdu610225 China

Optical metasurfaces have enabled high-speed, low-power image processing within a compact footprint. However, reconfigurable imaging in such flat devices remains a critical challenge for fully harnessing their potential in practical applications. Here, we propose and demonstrate phase-change metasurfaces capable of dynamically switching between edge detection and bright-field imaging in the visible spectrum. This reconfigurability is achieved through engineering angular dispersion at electric and magnetic Mie-type resonances. The customized metasurface exhibits an angle-dependent transmittance profile in the amorphous state of Sb2S3 meta-atoms for efficient isotropic edge detection, and an angle-independent profile in the crystalline state for uniform bright-field imaging. The nanostructured Sb2S3-based reconfigurable image processing metasurfaces hold significant potential for applications in computer vision for autonomous driving systems. Copyright © 2024, The Authors. All rights reserved.

关键词： Change detection

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Valorizing waste crab shells as renewable biomass fillers in polyaniline for ammonia gas detection

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Materials Today: Proceedings 2023年 88卷 23-32页

作者： Suhaimi N.F. Abdul Karim S.N. Jamion N.A. Baharin S.N.A. Yong S.K. Shahabuddin S. Raoov M. Sambasevam K.P. Advanced Material for Environmental Remediation (AMER) Research Group Faculty of Applied Sciences Universiti Teknologi MARA Cawangan Negeri Sembilan Kampus Kuala Pilah Negeri Sembilan Kuala Pilah 72000 Malaysia Faculty of Applied Sciences Universiti Teknologi Mara Selangor Shah Alam 40450 Malaysia Department of Science School of Technology Pandit Deendayal Energy University Knowledge Corridor Raisan Village Gujarat Gandhinagar 382007 India Department of Chemistry Faculty of Science Universiti Malaya Kuala Lumpur 50603 Malaysia Electrochemical Material and Sensor (EMas) Group Universiti Teknologi MARA Selangor Shah Alam 40450 Malaysia

Seafood waste possesses an interesting physicochemical characteristic that can be used to produce lucrative end products. In the present study, an attempt was made to valorize waste crab shells as renewable biomass fillers in the synthesis of polyaniline/crab shell (PANI/CS) composites. PANI was synthesized via chemical oxidative method and the waste CSs were added ex-situ into the as-synthesized emulsion of PANI. The physicochemical properties of PANI/CS composites were evaluated by Fourier transform infrared (FTIR), ultraviolet–visible (UV–Vis), X-ray diffraction (XRD) and scanning electron microscope (SEM) techniques. sensor responses of PANI/CS composites in different concentrations of NH3 gases were reported by using a multimeter with the aid of home-made gas chamber. PANI/CS 20% outperformed among all the prepared PANI/CS composites with a correlation coefficient of R2 = 0.9886. Hence, PANI/CS 20% was selected to undergo sensor performance studies such as selectivity, reusability, and long-term stability. PANI/CS 20% exhibited good selectivity towards NH3 gas in the presence of others interfering species such as hexane, acetone, diethyl ether and hydrochloric acid fumes and showed stability up to 1 week with 5 cycles of reusability. In conclusion, the study proved that waste biomass of CSs can be effectively incorporated into the PANI matrix and applied as an NH3 gas sensor with an excellent limit of detection of 9.8 ppm. © 2023

关键词： Biomass Bioresources Environment Gas sensors PANI Waste Management

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Generalized Metasurface Design for Polarization Reconstruction in a Single Snapshot

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Journal of Lightwave technology 2025年

作者： Xu, Wenhui Li, Hui Liu, Yufei Li, Jie Tan, Qi Xu, Hang Zhang, Yan Yao, Jianquan Tianjin University Key Laboratory of Opto-Electronics Information Technology Ministry of Education School of Precision Instruments and Opto-Electronics Engineering Tianjin300072 China Capital Normal University Beijing Key Laboratory for Metamaterials and Devices Key Laboratory of Terahertz Optoelectronics Ministry of Education Beijing Advanced Innovation Center for Imaging Technology Department of Physics Beijing100048 China Chengdu University of Information Technology Sichuan Meteorological Optoelectronic Sensor Technology and Application Engineering Research Center Chengdu610225 China

Metasurfaces enable the design of compact devices that can detect polarization with high precision. This capability is highly significant in applications where space and weight are constraints, such as in portable sensors, optical systems, or communications. Nevertheless, traditional metasurface-based polarization measurement techniques may not work efficiently at terahertz (THz) frequencies due to the different behavior of THz waves compared to visible light. In this work, we propose and experimentally demonstrate a design strategy for THz polarization recognition that utilizes all-dielectric metasurface. This approach necessitated only the extraction of the electric field distribution at the focal plane in the transmission mode. The focal spot located at the center of the focal plane carries orbital angular momentum (OAM), which assisted in determining the azimuthal angle of the incident polarization state. Furthermore, off-axis focal spot positioned in four quadrants provided additional information regarding ellipticity and enable characterization of both axis ratio and the handedness of the polarization ellipse. The pivotal information delineated by the Stokes parameter S3, the axial ratio (AR), and ellipticity (χ) can effectively identify arbitrary polarization states that encompass the entire surface of Poincaré sphere. The consistency between the experimental and simulated results confirms the effectiveness of the designed metasurface in accurately reconstructing THz polarization states. The ability of the designed metasurface to manipulate and detect polarization states with high precision can improve performance in imaging, sensing, and communication systems. © 1983-2012 IEEE.

关键词： Spin polarization

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Ultrafast polarization modulation with high-purity chiral quasi-BIC metasurfaces

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Chinese Optics Letters 2025年第5期 142-148页

作者：赖方兴范宇斌沙新博邓画春蒋雄肖淑敏黄灿宋清海 Ministry of Industry and Information Technology Key Lab of Micro-Nano Optoelectronic Information System Guangdong Provincial Key Laboratory of Semiconductor Optoelectronic Materials and Intelligent Photonic Systems Harbin Institute of Technology (Shenzhen) Department of Electrical Engineering City University of Hong Kong Heilongjiang Provincial Key Laboratory of Advanced Quantum Functional Materials and Sensor Devices

Precise control of the polarization state of light on ultrafast time scales plays a key role in revealing the inherent chiral or anisotropic optical responses in various material systems, and it is crucial for applications that require complex polarization encoding. Here, we explore ultrafast polarization control enabled by silicon-based chiral bound state in the continuum（BIC）metasurfaces. By utilizing the intrinsic chiral mode, we achieve high-purity chiral reflection light（S3～-0.92） and rapid modulation（～0.4 ps） of polarization states through all-optical methods. Unlike traditional polarization modulation techniques, our approach leverages the unique advantages of slanted etching dielectric chiral BIC metasurfaces, which facilitate high-Q resonance and exhibit narrow linewidths. These advantages allow swift alterations in polarization states with minimal modulation energy consumption, which should help for greater control of light in integrated photonic applications.

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