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49 results on '"Yang, Zhaoshu"'

11. Preparation, testing, and design of a radar‐absorption polymethacrylimide foam.

Author

Song, Shijun, Yuan, Jie, Duan, Rongxia, Xiong, Chao, Yin, Junhui, Zhao, Fang, Han, Chao, Yang, Zhaoshu, and Liu, Lei

Subjects
ABSORPTION, ELECTROMAGNETIC fields, PHENOXY groups, RADAR absorbers, FUNCTIONAL groups
Abstract

This article presents a new radar‐absorbing polymethacrylimide (RAPMI) foam, measures the electromagnetic (EM) parameters of the foam, and establishes mechanical prediction models. The reflection loss (RL) curves of foams with different thicknesses and absorbent weight ratios (wt%) were analyzed along with the shear and compression behaviors of the RAPMI foam. Gibson models of the RAPMI foam were then established. The parametric effects of the absorption performance of multilayered RAPMI foams were analyzed using multimedia transmission‐line theory. A numerically designed RAPMI foam exhibited excellent EM performance while retaining the outstanding mechanical properties of the original foam. The laminated foam can theoretically achieve a full‐band effective absorption (RL ≤ −10 dB) of 2–18 GHz with a minimal thickness of 33.1 mm. [ABSTRACT FROM AUTHOR]

Published
2024
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15. Preparation, testing, and design of a radar‐absorptionpolymethacrylimide foam

Author

Song, Shijun, Yuan, Jie, Duan, Rongxia, Xiong, Chao, Yin, Junhui, Zhao, Fang, Han, Chao, Yang, Zhaoshu, and Liu, Lei

Abstract

This article presents a new radar‐absorbing polymethacrylimide (RAPMI) foam, measures the electromagnetic (EM) parameters of the foam, and establishes mechanical prediction models. The reflection loss (RL) curves of foams with different thicknesses and absorbent weight ratios (wt%) were analyzed along with the shear and compression behaviors of the RAPMI foam. Gibson models of the RAPMI foam were then established. The parametric effects of the absorption performance of multilayered RAPMI foams were analyzed using multimedia transmission‐line theory. A numerically designed RAPMI foam exhibited excellent EM performance while retaining the outstanding mechanical properties of the original foam. The laminated foam can theoretically achieve a full‐band effective absorption (RL ≤ −10 dB) of 2–18 GHz with a minimal thickness of 33.1 mm.

Published
2024
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17. Modelling and Validation of Electret-Based Vibration Energy Harvesters in View of Charge Migration

Author

Yang, Zhaoshu, Tang, Lihua, Tao, Kai, and Aw, Kean C.

Abstract

One of the key problems of electret-based vibration energy harvester (eVEH) modelling is that the surface voltage itself cannot precisely reveal the charge storage characteristics of the electret fabricated by different processes. In this paper, we endeavor to interpret the charge migration mechanism of the eVEH with electrets fabricated by different processes. Based on the above analysis, a unified analytical model of the eVEH is derived accordingly. The dynamic response and voltage output predicted by this model are verified numerically by the equivalent circuit simulation and experimentally with an out-of-plane eVEH prototype. According to the analysis, the maximum power output is approximately 255 μW when the prototype works at its resonance frequency and the vibration amplitude is 1 mm. This paper elucidates the working principle of the eVEH and provides a framework for further theoretical study of eVEHs from the first principle.

Published
2024
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27. An electret-based thermoacoustic-electrostatic power generator

Author

Chen, Geng, Tang, Lihua, Yang, Zhaoshu, Tao, Kai, and Yu, Zhibin

Abstract

Sections\ud PDFPDF\ud Tools\ud Share\ud Summary\ud \ud This study reports a new concept for power generation from thermal energy, which integrates a thermoacoustic engine (TAE) with a contact‐free electret‐based electrostatic transducer. The TAE converts thermal energy into high‐intensity acoustic energy, while the electret‐based electrostatic transducer converts the generated acoustic energy into electricity. The experiments demonstrate the feasibility and potential of the proposed electret‐based thermoacoustic‐electrostatic power generator (TAEPG). The dynamic response of the electrostatic transducer and energy conversion inside the TAE are further investigated using a lumped element model and a frequency‐domain reduced‐order network model. Good agreement is achieved between experimental measurements and theoretical predictions. Furthermore, a parametric study is performed to study the effect of key parameters including the external heating power, air gap, and resistive load on the performance of the TAEPG. Results show that an open‐circuit voltage amplitude of 4.7 V is produced at a closed‐end pressure amplitude of 480 Pa in the experiment, and it is estimated that 25.2% of the acoustic power generated by the TAE has been extracted by the electret‐based electrostatic transducer. In this case, the maximum electric power output is measured to be 2.91 μW at a resistive load of around 2.2 MΩ. By increasing the external heating power, the TAEPG can produce a maximum voltage amplitude of 8 V. This work shows that the proposed concept has great potential for developing miniature heat‐driven power generators.

Published
2020

33. Displacement model of the giant magnetostrictive actuator with strong bias magnetic field at low frequency

Author

Zhang Peilin, Xue Guangming, He Zhongbo, Yang Zhaoshu, Li Dongwei, and Zhao Zhenglong

Subjects
Physics, Sine wave, Control theory, Magnetic reluctance, Mechanical Engineering, Acoustics, Linearity, Square wave, Actuator, Signal, Displacement (vector), Magnetic field
Abstract

A giant magnetostrictive actuator is designed with strong bias magnetic field. The influence of the strong bias field is introduced, and the corresponding exciting input signal is selected. Magnetic reluctance estimation, approximate linearity between the strain and magnetic field, and a mass–spring–damper system assumption are employed to analyze the actuator’s displacement with low-frequency signal input. An experimental system is designed, and properties of the proposed actuator are tested. With the help of square wave test, appropriate direction of exciting signal for the magnetostrictive actuator is determined. With the help of sinusoidal wave test, the established model is validated and the relationship between the maximum value of the displacement and of the current is analyzed. With exciting frequency lower than 200 Hz, the errors between the calculating and testing results are within 1.0 m, which validates the model.

Published
2016

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