Article
Chemistry, Physical
Zijian Liao, Mingliang Ma, Zhouyu Tong, Rongzhen Wang, Yuxin Bi, Yan Chen, Kwok L. Chung, Yong Ma
Summary: In this study, ZnFe2O4/C@PPy composites were prepared and showed excellent electromagnetic wave absorption performance, mainly attributed to dielectric loss and ideal impedance matching. The composites have great potential application as high-efficient absorption materials.
JOURNAL OF COLLOID AND INTERFACE SCIENCE
(2021)
Article
Chemistry, Physical
Qian Su, Bochong Wang, Congpu Mu, Kun Zhai, Anmin Nie, Jianyong Xiang, Fusheng Wen
Summary: The MoS2@Ppy composites were synthesized through microwave-assisted hydrothermal method, with MoS2 nanoparticles exhibiting three-dimensional flower-like structures and Ppy nanoparticles uniformly coated on the surface of MoS2. The composites showed enhanced complex permittivity due to the high conductivity of Ppy, leading to strong microwave absorption performance and potential application as high-efficiency microwave absorbers.
JOURNAL OF ALLOYS AND COMPOUNDS
(2021)
Article
Polymer Science
Huiru Yang, Aiping Wang, Xincong Feng, Hailing Dong, Tao Zhuang, Jing Sui, Shugao Zhao, Chong Sun
Summary: A novel microwave absorbing rubber containing homemade Polypyrrole nanotube (PPyNT) was developed based on natural rubber (NR) and acrylonitrile-butadiene rubber (NBR) blends to meet the comprehensive demand for flexible microwave absorbing materials. The content of PPyNT and NR/NBR blend ratio were adjusted to achieve optimal microwave absorbing performance in the X band. The 6 phr PPyNT filled NR/NBR (90/10) composite showed superior microwave absorbing performance with a minimum reflection loss value of -56.67 dB and an effective bandwidth of 3.7 GHz at a thickness of 2.9 mm.
Article
Chemistry, Physical
Leilei Zhang, Yihua Lv, Xiaoyun Ye, Lian Ma, Song Chen, Yuping Wu, Qianting Wang
Summary: ZnO/PPy composites with flower- and rod-like structures were successfully fabricated in this study, showing that the MWA ability was significantly enhanced after the introduction of PPy. Among them, the rod-like composites exhibited superior MWA properties compared to the flower-like ones, attributed to the improved dielectric properties and multiple reflections of incident electromagnetic waves.
Editorial Material
Chemistry, Physical
Yuxin Bi, Mingliang Ma, Yanyan Liu, Zhouyu Tong, Rongzhen Wang, Kwok L. Chung, Aijie Ma, Guanglei Wu, Yong Ma, Changpeng He, Pan Liu, Luying Hu
Summary: The CoZn/C@MoS2@PPy composites prepared through MOF self-template method showed enhanced microwave absorption performance with optimized impedance matching. The introduction of MoS2 sheets and PPy shell improved the absorption bandwidth, demonstrating better performance than CoZn/C composites under lower thickness.
JOURNAL OF COLLOID AND INTERFACE SCIENCE
(2021)
Article
Materials Science, Multidisciplinary
Songyan Li, Xiaoxia Tian, Jiafu Wang, Lisi Ma, Chenchen Li, Zhe Qin, Shaobo Qu
Summary: This study successfully improved the microwave absorption performances of carbonyl iron powder by constructing a heterogeneous core-shell structure using multiwalled carbon nanotubes and binder Polypyrrole. By changing the thickness of the shell, the microwave absorption performances of the composites can be adjusted effectively, showing excellent microwave reflection loss and absorption bandwidth, which makes it a promising candidate for microwave absorption materials.
DIAMOND AND RELATED MATERIALS
(2022)
Article
Chemistry, Physical
Jin Cui, Xihua Wang, Li Huang, Chengwei Zhang, Ye Yuan, Yibin Li
Summary: In this study, bark-derived cobalt-doped porous carbon composites for microwave absorption applications were successfully prepared through a simple method, and the microwave absorption performance could be further enhanced by adjusting the carbonization temperature of the bark. The retained channel structures of the bark and dispersed cobalt nanoparticles on the surface played a key role in the excellent microwave absorption performance.
Article
Chemistry, Physical
Yi Chen, Rong Qiang, Yulong Shao, Jiawen Qiu, Qian Ma, Xiao Yang, Rui Xue, Bowen Chen, Shijiang Feng, Yuancheng Ding
Summary: Magnetic metal modified carbon-based composites synthesized through chemical methods have shown great potential in the field of electromagnetic wave absorption. This study embedded magnetic iron ions in dried agaric and obtained ripple-like Fe/Ccomposites after high-temperature annealing. The Fe/Ccomposites have broadband electromagnetic response and excellent absorption performance.
JOURNAL OF ALLOYS AND COMPOUNDS
(2023)
Article
Engineering, Environmental
Renxin Xu, Dewen Xu, Zhe Zeng, Dan Liu
Summary: An ultralight magnetic-carbon hybrid material was designed to achieve superior microwave absorption performances through self-assembly and compositional control, offering new insights for designing highly effective microwave absorbers.
CHEMICAL ENGINEERING JOURNAL
(2022)
Article
Materials Science, Ceramics
Xiaojun Chen, Hongyang Liu, Dechao Hu, Huaqing Liu, Wenshi Ma
Summary: Carbon nanotubes have emerged as a potential candidate to address issues related to electromagnetic pollution and interference, offering advantages like high dielectric loss and remarkable thermodynamic stability. Recent advances in CNTs-based microwave absorbing materials have shown promising prospects, particularly in the development of composites for better microwave absorption capabilities.
CERAMICS INTERNATIONAL
(2021)
Article
Chemistry, Physical
Hui Luo, Sihai Lv, Guizhen Liu, Yongzhi Cheng, Xujin Ge, Xian Wang, Rongzhou Gong, Fu Chen
Summary: Developing high-performance microwave absorbing materials remains a challenge in addressing electromagnetic pollution. This study focuses on interfacial engineering to enhance interfacial polarization, which plays a key role in microwave absorption. The researchers prepared multiple interfacial magnetic carbon nanotubes encapsulated hydrangea-like NiMo/MoC/N-doped carbon via carbothermic reduction. The phase structure and electromagnetic properties were regulated by varying the thermal treatment temperature. Dielectric loss mechanisms were analyzed using Debye relaxation theory. The composites exhibited excellent microwave absorption properties, achieving a reflection loss of less than -20 dB in the frequency range of 3.76-17.52 GHz. The highest reflection loss value of -70.1 dB was achieved at 14.2 GHz with an absorber thickness of only 1.52 mm at a thermal treatment temperature of 800°C. Computer simulation technology was used to analyze the radar cross section (RCS) reduction, with a reduction of 17.05 dBm2 observed at a scattering angle of 0. This work provides a novel approach for achieving multi-interface absorbers for high-performance microwave absorption.
Article
Materials Science, Ceramics
Muhammad Adnan Aslam, Kang Hu, Wei Ding, Ali Hassan, Yuecheng Bian, Kang Qiu, Qiangchun Liu, Zhigao Sheng
Summary: By changing the dimensionality of bio-carbon materials, the microwave absorption properties of ferrite/carbon composites can be effectively improved, with the minimum reflection loss enhanced from -9 dB to -45 dB. Adjusting the thickness of ZFO/3D-bio-carbon samples allows for a wide absorption range from 4 to 18 GHz, with an effective absorption bandwidth up to 7.1 GHz covering the entire Ku band.
CERAMICS INTERNATIONAL
(2021)
Article
Materials Science, Ceramics
G. Logesh, Ummen Sabu, C. Srishilan, Mohammed Rashad, Andrews Joseph, K. C. James Raju, M. Balasubramanian
Summary: The hybrid network of Si3N4 and conducting carbon fiber shows great potential for microwave absorption applications. The composition of carbon fiber in the composites can be adjusted to control their microwave absorption performance, with lower carbon fiber content showing better absorption performance, suitable for various thickness requirements.
CERAMICS INTERNATIONAL
(2021)
Article
Chemistry, Physical
Zijian Liao, Mingliang Ma, Zhouyu Tong, Yuxin Bi, Kwok L. Chung, Mingtao Qiao, Yong Ma, Aijie Ma, Guanglei Wu, Zongxuan Li, Yu Zhang
Summary: The one-dimensional ZnFe2O4@carbon@MoS2/FeS2 composites synthesized in this work exhibit strong microwave absorption capacity, making them a promising material for electromagnetic wave absorption applications. The study provides new insights into the research and application of electromagnetic wave absorption materials.
JOURNAL OF COLLOID AND INTERFACE SCIENCE
(2021)
Article
Chemistry, Physical
Xiaohui Liang, Gehuan Wang, Weihua Gu, Guangbin Ji
Summary: Different carbon-based composites derived from metal organic frameworks (MOFs) have shown significant tuning effects on microwave absorption through various annealing atmospheres, demonstrating excellent performance under different thicknesses. These composites have promising applications due to their strong microwave attenuation capability and broad effective absorption bandwidth.
Article
Physics, Multidisciplinary
Ying Liu, Yue Liu, Michael G. B. Drew
Summary: The quarter-wavelength model suggests that the reflection of microwaves can be minimized by adjusting the film thickness to m lambda/4, where m is an odd integer and lambda is the wavelength within the film. However, this study challenges the validity of the model and proposes an alternative approach based on wave superposition principles. The study also criticizes the inappropriate use of certain concepts in current mainstream microwave absorption theory, such as the characterization of microwave absorption using reflection loss RL from materials.
Article
Materials Science, Multidisciplinary
Ying Liu, Yue Liu, Michael G. B. Drew
Summary: For many years, it has been common practice to use reflection loss defined for devices to characterize materials, which has caused many problems. By replacing the flawed theory of impedance matching with wave superposition theory and using simple geometry to represent film absorption, the real mechanism of film absorption has been revealed. It is shown that film and material are different, and absorption efficiency is influenced by factors such as wave superposition and energy conservation.
MATERIALS CHEMISTRY AND PHYSICS
(2022)
Article
Materials Science, Multidisciplinary
Ying Liu, Yue Liu, Michael G. B. Drew
Summary: This section discusses the application of impedance matching and quarter-wavelength theories in microwave absorption research, pointing out their flaws and proposing a new theory to replace the quarter-wavelength theory.
MATERIALS CHEMISTRY AND PHYSICS
(2022)
Article
Materials Science, Multidisciplinary
Ying Liu, Yue Liu, Michael G. B. Drew
Summary: Energy conservation is crucial for understanding the mechanism of microwave absorption by films. In the past, confusion between films and materials has caused many issues. By considering energy conservation, the differences between films and materials are clarified, and some difficult issues have been explained.
MATERIALS CHEMISTRY AND PHYSICS
(2022)
Article
Chemistry, Multidisciplinary
Jiahe Song, Kun Zhao, Xiangbin Yin, Ying Liu, Iltaf Khan, Shu-Yuan Liu
Summary: A Z-scheme g-C3N4/Ag/AgBr heterojunction photocatalyst was prepared via in-situ loading through photoreduction method. The g-C3N4/Ag/AgBr composite showed excellent photocatalytic performance in the degradation of tetracycline hydrochloride pollutants. The main active oxygen species involved in the degradation of organic pollutants were O2^- and (OH)·.
FRONTIERS IN CHEMISTRY
(2022)
Article
Physics, Applied
Ying Liu, Michael G. B. Drew, Yue Liu
Summary: In the previous Part I, it was demonstrated using transmission-line theory that impedance matching theory should be replaced by wave cancellation theory. It was also shown that film is different from the material and phase effects from interfaces should be considered in quarter wavelength theory. In this Part, it is proven that energy penetration in a film cannot be defined and impedance matching is flawed as it lacks theoretical proof and consistency with experimental data. The multiple absorption peaks in a film arise from wave cancellation under the constraint of energy conservation, rather than resonances from the material.
JOURNAL OF APPLIED PHYSICS
(2023)
Article
Physics, Applied
Ying Liu, Michael G. B. Drew, Yue Liu
Summary: This study theoretically confirms that the absorption mechanism in a film, responsible for the minima of the reflection loss (RL/dB), is best explained by wave cancelation theory rather than by impedance matching theory. The study also reveals that the mechanisms for a film and material are different. In addition, the flaws of neglecting the phase effects of interfaces in a film in quarter-wavelength theory are quantitatively discussed.
JOURNAL OF APPLIED PHYSICS
(2023)
Article
Physics, Condensed Matter
Ying Liu, Xiangbin Yin, Michael G. B. Drew, Yue Liu
Summary: By analyzing experimental data, this study provides new theoretical perspectives on the inadequacies of impedance matching theory in the field of microwave absorption. It suggests that the current theories related to impedance matching need to be replaced by wave cancellation theory, as even different criteria cannot solve the problems with impedance matching. The analysis in this work supports the new theories against the current ones by applying to published data and determining the conditions for the minima of reflection loss at large values of |Zin - Z0| through transmission-line theory.
PHYSICA B-CONDENSED MATTER
(2023)
Article
Chemistry, Physical
Ying Liu, Yi Ding, Yue Liu, Michael G. B. Drew
Summary: It is commonly believed that two synergistic effects maximize microwave absorption power of a film - increasing the absorption power of the material and the penetration of incident microwaves into the film. However, this reasoning is incorrect as it confuses material with film and is not consistent with the real absorption mechanism. By differentiating film from material, it is shown that reflection loss (RL) is relevant only for film and the real mechanism involves balancing the intensities of the two beams reflected from the film's interfaces when they are out of phase by π. It is commonly believed incorrectly that maximum absorption from film occurs when the resultant beam reflected back to open space from the metal-back interface is weakest. But it is shown here that the opposite is true - maximum absorption occurs when this reflected beam reaches its maximum. A definition for film in the context of microwave absorption is proposed.
SURFACES AND INTERFACES
(2023)
Article
Chemistry, Physical
Ying Liu, Yi Ding, Yue Liu, Michael G. B. Drew
Summary: Part 1 of this work demonstrates that film absorption is based on wave cancellation theory (WCT) rather than the mechanism of material attenuation power and impedance matching theory (IM). The film thickness and material properties affect the pattern of the reflection loss curve and the occurrence of multiple absorption peaks. Maximum absorption occurs when the two reflected beams are out of phase by & pi; at the front of the film, regardless of whether the film has a metal back or not. WCT explains the deviations of maximum absorption positions from the predicted values of IM.
SURFACES AND INTERFACES
(2023)
