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292 results on '"Yi, Yougen"'

57. Graphene Multi-Frequency Broadband and Ultra-Broadband Terahertz Absorber Based on Surface Plasmon Resonance.

Author

Chen, Zihao, Cai, Pinggen, Wen, Qiye, Chen, Hao, Tang, Yongjian, Yi, Zao, Wei, Kaihua, Li, Gongfa, Tang, Bin, and Yi, Yougen

Subjects
SURFACE plasmon resonance, FINITE difference time domain method, GRAPHENE, PHOTOELECTRICITY, SURFACE plasmons, RESONANT tunneling, ELECTROMAGNETIC shielding, FREQUENCY spectra
Abstract

When surface plasmon resonance (SPR) occurs, the incident light is absorbed by the surface of the SPR structure, thus minimizing the intensity of the reflected light. Therefore, the SPR method is adopted in this paper to achieve perfect absorption of the absorbent. In this paper, we first propose a multi-frequency broadband absorber structure based on graphene SPR, which uses the continuous resonance of patterned graphene surface plasmon in the frequency spectrum to form a multi-frequency broadband absorption. In this simulation, a sandwich-stack structure was adopted, whereby the patterned graphene is situated on top of the SiO2 layer and the metal layer. The broad-band absorption bands of the absorber were obtained as 4.14–4.38 THz, 5.78–6.36 THz, and 7.87–8.66 THz through the analog simulation of finite-difference time-domain method (FDTD) solutions. Then, based on the multi-layer resonant unit structure, through the superposition and combination of absorbing units responding to different frequency bands, the perfect absorption of ultra-wideband is achieved. The data results illustrate that the total absorption bandwidth of the absorber is 2.26 THz, and the relative absorption bandwidth Bw is equal to 28.93%. The electric field in X-Y direction of the absorber in the perfect absorption band is analyzed, respectively, and the dynamic tunability of the absorber is studied. Finally, we studied whether the absorbing structure still has efficient absorption characteristics for the two polarization modes when the incident angle is changed from 0° to 70°. The structure model proposed has potential value for application in terahertz photoelectric detection, filtering, and electromagnetic shielding. [ABSTRACT FROM AUTHOR]

Published
2023
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58. Study on the Thermal Distribution Characteristics of a Molten Quartz Ceramic Surface under Quartz Lamp Radiation.

Author

Chen, Hao, Li, Wei, Zhu, Shimin, Hou, Aiqiang, Liu, Tao, Xu, Jiangshan, Zhang, Xiaowei, Yi, Zao, Yi, Yougen, and Dai, Bo

Subjects
HEAT resistant materials, FUSED silica, CERAMIC materials, CERAMICS, RADIATION, FUSED salts, SPEED of sound, THERMAL insulation, QUARTZ
Abstract

More and more researchers are studying the heat transfer performance of aeronautical materials at high temperatures. In this paper, we use a quartz lamp to irradiate fused quartz ceramic materials, and the sample surface temperature and heat flux distribution were obtained at a heating power of 45~150 kW. Furthermore, the heat transfer properties of the material were analyzed using a finite element method and the effect of surface heat flow on the internal temperature field was investigated. The results show that the fiber skeleton structure has a significant effect on the thermal insulation performance of fiber-reinforced fused quartz ceramics and the longitudinal heat transfer along the rod fiber skeleton is slower. As time passes, the surface temperature distribution tends to stability and reaches an equilibrium state. The surface temperature of fused quartz ceramic increases with the increase in the radiant heat flux of the quartz lamp array. When the input power is 5 kW, the maximum surface temperature of the sample can reach 1153 °C. However, the non-uniformity of the sample surface temperature also increases, reaching a maximum uncertainty of 12.28%. The research in this paper provides important theoretical guidance for the heat insulation design of ultra-high acoustic velocity aircraft. [ABSTRACT FROM AUTHOR]

Published
2023
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63. High Absorptivity and Ultra-Wideband Solar Absorber Based on Ti-Al 2 O 3 Cross Elliptical Disk Arrays.

Author

Zhang, Yuanjian, Yi, Yingting, Li, Wenxin, Liang, Shiri, Ma, Jing, Cheng, Shubo, Yang, Wenxing, and Yi, Yougen

Subjects
FINITE difference time domain method, SURFACE plasmon resonance, SOLAR radiation, ENERGY harvesting, SOLAR energy
Abstract

Perfect metamaterial absorbers have attracted researchers' attention in solar energy harvesting and utilization. An ideal solar absorber should provide high absorption, be ultra-wideband, and be insensitive to polarization and incident angles, which brings challenges to research. In this paper, we proposed and optimized an ultra-wideband solar absorber based on Ti-Al2O3 cross elliptical disk arrays to obtain the ultra-wideband absorption of solar energy. The addition of a cavity greatly improves the energy-absorbing effect in the operating band, which has research value. The absorption spectrum and field distribution were analyzed by the finite difference time domain method. For the physical mechanism, the electric and magnetic field distribution indicates that ultra-wideband absorption is caused by propagation surface plasmon resonance (SPR), localized SPR and Fabry–Perot (F-P) resonance excited between Ti and Al2O3 disks. The results demonstrate that the absorption bandwidth with the absorption rate beyond 90% reaches 1380 nm (385–1765 nm), and the average absorption reaches an astonishing 98.78%. The absorption bandwidth matches the main radiation bandwidth of the solar energy, which is approximately 295–2500 nm according to the data from the literature, and the total thickness of the structure is only 445 nm. Moreover, the ultra-wideband solar absorber is insensitive to the polarization angle and oblique incidence angle. The proposed ultra-wideband solar absorber has research and application value in solar energy harvesting, photothermal conversion and utilization. [ABSTRACT FROM AUTHOR]

Published
2023
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81. Effect of slit width on surface plasmon resonance

Author

Wang, Yingying, primary, Qin, Feng, additional, Yi, Zao, additional, Chen, Xifang, additional, Zhou, Zigang, additional, Yang, Hua, additional, Liao, Xu, additional, Tang, Yongjian, additional, Yao, Weitang, additional, and Yi, Yougen, additional

Published
2019
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100. Fabrication and ultraviolet photoemission characteristics of novel Au photocathodes

Author

吴卫东 Wu Weidong, 曹柱荣 Cao Zhurong, 王雪敏 Wang Xuemin, 徐习斌 Xu Xibin, 易早 Yi Zao, 高扬 Gao Yang, 易有根 Yi Yougen, and 王瑜英 Wang Yuying

Subjects
Fabrication, Materials science, business.industry, Annealing (metallurgy), Nanoparticle, medicine.disease_cause, Atomic and Molecular Physics, and Optics, Cathode, law.invention, Sputtering, law, Secondary emission, medicine, Optoelectronics, Electrical and Electronic Engineering, Thin film, business, Ultraviolet
Published
2013

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