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Broadband planar electromagnetic hyper-lens with uniform magnification in air

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arXiv 2024年

作者： Sun, Ran Sun, Fei Chen, Hanchuan Liu, Yichao Wang, Qi Key Lab of Advanced Transducers and Intelligent Control System Ministry of Education and Shanxi Province College of Electronic Information and Optical Engineering Taiyuan University of Technology Taiyuan030024 China

A planar hyper-lens, capable of creating sub-wavelength imaging for broadband electromagnetic wave, is designed based on electromagnetic null medium. Subsequently, a scheme for the implementation of the proposed hyper-lens is given by using well-designed flexural metal plates, which function as the reduced electromagnetic null medium for TM-polarized microwaves. Both simulated and measured results verify that the hyper-lens designed with flexural metal plates can achieve super-resolution imaging for microwave at operating wavelength (λ0=3cm) with a resolution of 0.25λ0 and a uniform magnification of about 5. Moreover, the designed hyper-lens ensures that both the object and image surfaces are planes, and simultaneously provides a uniform magnification for objects in different positions. Additionally, the proposed hyper-lens offers a broadband superresolution imaging capabilities, achieving good super-resolution imaging effects for microwave frequencies ranging from 8.5 to 11 GHz. The proposed hyper-lens may find applications in high precision imaging, detection, and sensing. Copyright © 2024, The Authors. All rights reserved.

关键词： optical resolving power

On-chip omnidirectional electromagnetic-thermal cloak

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arXiv 2023年

作者： Liu, Yichao Chen, Hanchuan Zhao, Gang Sun, Fei Key Lab of Advanced Transducers and Intelligent Control System Ministry of Education and Shanxi Province College of Electronic Information and Optical Engineering Taiyuan University of Technology Taiyuan030024 China

Simultaneously guiding electromagnetic waves and heat flow at any incidence angle to smoothly bypass some electromagnetic/thermal sensitive elements is a key factor to ensure efficient communication and thermal protection for an on-chip system. In this study, an omnidirectional on-chip electromagnetic-thermal cloak is proposed. Firstly, a holey metallic plate with periodic array of subwavelength apertures is designed by optical surface transformation to realize an omnidirectional electromagnetic cloaking module for on-chip electromagnetic signal. Secondly, a two-layer ring-shaped engineered thermal structure is designed by solving Laplace equation to realize an omnidirectional thermal cloaking module for in-chip heat flow. Finally, these two cloaking modules are combined elaborately to achieve cloaking effect for both the electromagnetic waves and thermal fields simultaneously from any detecting direction, thus protecting the build-in electromagnetic/thermal sensitive elements without disturbing the external electromagnetic/thermal signal. The proposed electromagnetic-thermal cloak may have potential advantage in dealing with omnidirectional electromagnetic compatibility/shielding and multi-directional thermal management/dissipation of an on-chip system. Copyright © 2023, The Authors. All rights reserved.

关键词： Heat transfer

Ultra-broadband acoustic absorber based on periodic acoustic rigid-metaporous composite array

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arXiv 2024年

作者： Zhang, Dongguo Sun, Fei Liu, Yichao Key Lab of Advanced Transducers and Intelligent Control System Ministry of Education and Shanxi Province College of Electronic Information and Optical Engineering Taiyuan University of Technology Taiyuan030024 China

To address the increasingly serious issue of noise pollution, we propose an ultra-broadband and wide-angle acoustic absorber based on a periodic acoustic rigid-metaporous composite array. Numerical simulation results verify the broadband good acoustic absorption performance of the proposed absorber, which can achieve an average absorption coefficient of approximately 90.9% within the frequency band from 500 to 4000 Hz with incident angles ranging from -75 to +75 degrees, thus compensating for the shortcomings of traditional acoustic absorbers that are not as effective at low frequencies. This work will provide a new approach for ultra-broadband and wide-angle acoustic wave absorption and noise suppression. Copyright © 2024, The Authors. All rights reserved.

关键词： Acoustic wave absorption

Calculating the Induced Electric Fields in Real Human Head by Transcranial Magnetic Stimulation Using Coil Array

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Calculating the Induced Electric Fields in Real Human Head b...

第七届电磁辐射与健康国际研讨会

作者： Mai Lu Shoogo Ueno Key Lab of Opt-Electronic Technology and Intelligent Control of Ministry of Education Lanzhou Jiaotong University Lanzhou 730070 P.R.China Department of Applied Quantum Physics Graduate School of Engineering Kyushu University Fukuoka 812-8581 Japan

Depemdence of Specific Absorption Rate on the Size of the Head Model in Mobile Phone Dosimetry

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Depemdence of Specific Absorption Rate on the Size of the He...

第七届电磁辐射与健康国际研讨会

Experimental demonstration of a thermal-EM concentrator for enhancing EM signals and converging heat fluxes simultaneously

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arXiv 2024年

作者： Chen,, Hanchuan Liu,, Yichao Sun,, Fei Sun, Qianhan Wu,, Xiaoxiao Sun, Ran Key Lab of Advanced Transducers and Intelligent Control System Ministry of Education and Shanxi Province College of Electronic Information and Optical Engineering Taiyuan University of Technology Taiyuan030024 China Guangzhou510000 China

Simultaneously concentrating EM waves and heat fluxes to the same target region within an on-chip system carries substantial academic research importance and practical application value. Nevertheless, existing researches are primarily aimed at the design and experimentation of concentrators for individual EM waves or temperature fields. In this work, a thermal-EM concentrator, capable of simultaneously concentrating EM waves and heat fluxes, is designed using transformation optics/thermodynamics and fabricated with engineered EM-thermal metamaterials. The concentrating effects of the proposed thermal-EM concentrator on the thermal fluxes and EM waves are verified through numerical simulations and experimental measurements, respectively, which are in good agreement with each other. Both numerically simulated and experimentally measured results demonstrate the concentrating capability of the proposed thermal-EM concentrator, which can concentrate broadband TM-polarized EM waves ranging from 8-12 GHz and heat/cold flows to the same target region within an on-chip operating environment. The thermal-EM concentrator exhibits a thermal focusing efficiency close to 100% and more than three times enhancement of the magnetic field at the designed center frequency of 10 GHz. The proposed thermal-EM concentrator can be utilized for efficient cooling for the specified component and simultaneously enhancing the EM antenna's radiation/reception efficiency within an on-chip system. Copyright © 2024, The Authors. All rights reserved.

关键词： Heat flux

Tunable uniform field enhancement in a subwavelength air pillar by photonic doping in epsilon-near-zero medium

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Results in Physics 2024年 61卷

作者： Sun, Fei Shan, Jinyuan Liu, Yichao Zhao, Xiaodan Key Lab of Advanced Transducers and Intelligent Control System Ministry of Education and Shanxi Province College of Electronic Information and Optical Engineering Taiyuan University of Technology Taiyuan 030024 China

In this study, a novel electric field compressor is proposed by doping a metal-air-metal pillar in epsilon-near-zero medium within a metallic waveguide, which effectively enhances the background electric fields in a sub-wavelength air pillar with high uniformity. The field enhancement factor can be analytically determined through theoretical derivations from Maxwell's equations, reaching its maximum value by appropriately selecting the size of the air pillar. Furthermore, the proposed compressor can achieve a tunable electric field enhancement effect within the deep sub-wavelength air pillar by adjusting the height of the air pillar through movement of two metal pillars inserted into the waveguide. Both theoretical analysis and numerical simulations are employed to validate the performance of the electric field compressor, which exhibits a wide range of tunable field enhancement effect (i.e., continuously adjustable enhancement factor between 20 and 800) with uniformity below 1.5 within the deep sub-wavelength air pillar (wherein the air volume is smaller than λ₀/10 × λ₀/10 × λ₀/16). Finally, a practical model is proposed for the realization of the electric field compressor in the microwave range, where specially placed metal pillars and wires are incorporated into a rectangular metallic waveguide structure. The field enhancement and tunable effects of this practical model have been verified through simulations. © 2024

关键词： Epsilon-near-zero medium Photonic doping Subwavelength field confinement Tunable enhancement

Comparation of Aroma-Active Compounds in Fresh Commercial Infant Formula and the Change during Ambient Storage

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Journal of Future Foods 2025年

作者： Lirong Xu Ailing Tian Jiayi Su Meifan Pan Riqing Liu Peipei Gao Beilei Pang Zitong Liu Lijiao Fan Huaixia Zhang Yali Wang Lei Du Lili Zheng Yingchun Zhao Xiaoxiao Feng Jing Lv Department of Nutrition The Affiliated Hospital of Qingdao University Qingdao China Institute of Nutrition and Health Qingdao University 266071 Qingdao China Department of Gastrointestinal Surgery The Affiliated Hospital of Qingdao University Jiangsu Road 16# Qingdao Shandong 266400 People's Republic of China Department of Health Education and Management and the Ministry of Education Key Lab of Hazard Assessment and Control in Special Operational Environment School of Public Health Fourth Military Medical University Xi'an China. Department of surgery The Affiliated Hospital of Qingdao University Qingdao China National Engineering Research Centre for Intelligent Electrical Vehicle Power System (Qingdao) College of Mechanical & Electronic Engineering Qingdao University Qingdao 266071 China College of Chemical Engineering Qingdao University of Science and Technology Analysis and Testing Center Qingdao University of Science and Technology 266042 Qingdao China Department of Food Science & Technology School of Agriculture & Biology Shanghai Jiao Tong University Shanghai 200240 China

This study compared the aroma-active compounds in 14 brands of commercially infant formula and investigated their changes during ambient storage after opening for 2 months. A total of 29 major aroma-active compounds were detected in infant formula. From the PCA and heatmap analysis, a total of 14 brands of infant formula were classified into 3 groups, the second group contained JLB-Y, AY and FH-F, of which 2-furanmethanol and (E,E)-3,5-octadien-2-one were mainly compounds, the third group contained YL and JLB-L, the characteristic flavor compounds in this group were mainly hexanal, heptanal, etc. Aldehydes, as the main volatile substances, account for more than half of the total volatiles. Nearly half of the aldehydes showed more significant changes after storage, e.g. hexanal, octanal, (E)-2-octenal and 3-methylbutyraldehyde. The YL and YP-Q produced more saturated aldehydes after storage, the concentration of hexanal in YL-2m and YP-Q-2m was 2138.5 μg/kg and 2004.1μg/kg, respectively. The concentrations of heptanal, octanal, and nonanal also increased relatively significantly, which may lead to a distinct rancid flavor in YL and YP-Q. Besides, among the ketones, (E,E)-3,5-octadien-2-one showed the greatest change after storage, especially in JLB-L. According to sensory evaluation experiments, the milky flavor of infant formulas decreased and fatty, rancid, fishy and grassy flavors were found to have increased to different extents after storage. The current information gap on the concentration and evolution of volatile compounds in commercially available infant formula is filled by this study.

关键词： Infant formula Volatile compounds GC-MS Ambient Storage

Occupational Exposure of Therapeutic Staff in Deep Transcranial Magnetic Stimulation

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Occupational Exposure of Therapeutic Staff in Deep Transcran...

General Assembly and Scientific Symposium, URSI

作者： Mai Lu Shoogo Ueno Key Lab. of Opto-Electronic Technology and Intelligent Control of Ministry of Education Lanzhou Jiaotong University Lanzhou P.R. China Department of Biomedical Engineering Graduate School of Medicine The University of Tokyo Tokyo Japan

This study presented dosimetry analysis for therapeutic staff exposed to magnetic pulses from double cone and Halo-circular assembly (HCA) coils during deep transcranial magnetic stimulation (dTMS) applications. The magnetic field and the induced electric field in realistic human body model exposure to dTMS coils have been obtained by employing the impedance method. The exposure level by both double cone and HCA coils were assessed according to the limits defined by the International Commission on Non-Ionizing Radiation Protection (ICNIRP) guidelines. The HCA coil generates higher exposure to therapeutic staff compared to that of double cone coil.

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