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Amorphous Bimetallic Nanowires with High-Performance Microwave Absorption: A Case for FeCo Nanowires
Junyao Shen,Yongtao Yao,Yanju Liu,Jinsong Leng 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2019 NANO Vol.14 No.4
Amorphous FeCo nanowires (NWs) with the average diameter of 120 nm were successfully prepared with a magnetic-field-assisted (MFA) hydrothermal method. Rapid reaction time was adopted to obtain amorphous FeCo NWs, being checked by XRD and TEM. Tuning the stoichiometric ratio of Fe/Co content meets the optimal impedance matching under different absorption frequency, making both improved intensities and frequency ranges of microwave absorption. For example, under 3mm coating thickness, the reflection loss (RL) peaks of Fe3Co7, Fe5Co5 and Fe7Co3 NWs are -25.88 dB at 4 GHz, -19.06 dB at 4.24 GHz and -21.98 dB at 5.44 GHz. The related efficient absorption bandwidths (fE < -10 dB) of Fe3Co7 NWs, Fe5Co5 NWs and Fe7Co3 NWs are 5.40 GHz, 3.52 GHz and 4.91GHz, respectively. It is ascribed to integrating enhanced dielectric/conductive losses, negligible damages from eddy current effect and good impedance matching for high-performance FeCo NWs absorbers. This work paves a new path on synthesizing bimetallic wire-like nanostructures for microwave absorption demands.
Shuai Liu,Li Wei,Yicheng Zhang,Yongtao Yao 전력전자학회 2015 JOURNAL OF POWER ELECTRONICS Vol.15 No.2
The application of soft-switching techniques is increasing in the DC/DC converter area. It is important to design soft-switching parameters to ensure the converter operates properly and efficiently. An optimized design method is presented in this paper. The objective function is the total power loss of a converter, while the variables are soft-switching parameters and the constraints are the electrical requirements for soft-switching. Firstly, a response surface methodology (RSM) model with a high precision is built, and the rough optimized parameters can be obtained with the help of a genetic algorithm (GA) in the solution space determined by the constraints. Secondly, a re-optimization is conducted with a SPICE model and a GA, and accurate optimized parameters can be obtained. Simulation and experiment results show that the proposed method performs well in terms of a wide adaptability, efficiency, and global optimization.
Liu, Shuai,Wei, Li,Zhang, Yicheng,Yao, Yongtao The Korean Institute of Power Electronics 2015 JOURNAL OF POWER ELECTRONICS Vol.15 No.2
The application of soft-switching techniques is increasing in the DC/DC converter area. It is important to design soft-switching parameters to ensure the converter operates properly and efficiently. An optimized design method is presented in this paper. The objective function is the total power loss of a converter, while the variables are soft-switching parameters and the constraints are the electrical requirements for soft-switching. Firstly, a response surface methodology (RSM) model with a high precision is built, and the rough optimized parameters can be obtained with the help of a genetic algorithm (GA) in the solution space determined by the constraints. Secondly, a re-optimization is conducted with a SPICE model and a GA, and accurate optimized parameters can be obtained. Simulation and experiment results show that the proposed method performs well in terms of a wide adaptability, efficiency, and global optimization.