Nanocasting synthesis of Fe3O4@HTC nanocapsules and their superior electromagnetic properties

RSC Advances ◽  
2016 ◽  
Vol 6 (24) ◽  
pp. 20386-20391 ◽  
Author(s):  
Zhihong Yang ◽  
Tong Xue ◽  
Linghui Yu ◽  
Guangbin Ji ◽  
Guoyue Xu ◽  
...  
Keyword(s):  
Electromagnetic Wave ◽  
Wave Attenuation ◽  
Electromagnetic Properties

Fe3O4@HTC nanocapsules synthesized using a nanocasting method exhibited enhanced electromagnetic wave attenuation properties.

scholarly journals High-efficiency and dynamic stable electromagnetic wave attenuation for La doped bismuth ferrite at elevated temperature and gigahertz frequency

RSC Advances ◽  
2015 ◽  
Vol 5 (94) ◽  
pp. 77184-77191 ◽  
Author(s):  
Yong Li ◽  
Mao-sheng Cao ◽  
Da-wei Wang ◽  
Jie Yuan
Keyword(s):  
Electromagnetic Wave ◽  
High Temperature ◽  
Elevated Temperature ◽  
High Efficiency ◽  
Wave Attenuation ◽  
Bismuth Ferrite ◽  
Electromagnetic Properties ◽  
Temperature Environment ◽  
La Doped ◽  
High Temperature Environment

La doped bismuth ferrite with enhanced electromagnetic properties exhibits high-efficiency and stable electromagnetic wave attenuation at dynamic high-temperature environment.

Core–Shell Structural Barium Ferrite/Polypyrrole Nanocomposites with Enhanced Microwave Absorption Properties

2020 ◽  
Vol 15 (11) ◽  
pp. 1312-1320
Author(s):  
Kai Sun ◽  
Gang Li ◽  
Yan-Hua Lei ◽  
Xin-Feng Wu ◽  
Wei-Guo Zhang ◽  
...  
Keyword(s):  
Electromagnetic Wave ◽  
Microwave Absorption ◽  
Barium Ferrite ◽  
Wave Attenuation ◽  
Magnetic Loss ◽  
Impedance Matching ◽  
Oxidative Polymerization ◽  
Electromagnetic Properties ◽  
Core Shell ◽  
Absorption Performance

In this paper, core–shell structural barium ferrite/polypyrrole (BF/PPy) nanocomposites were prepared by a facile in-situ chemical oxidative polymerization method, and their electromagnetic properties were systematically studied. It was demonstrated that the nanocomposites with 15 mol% BF possessed the best electromagnetic wave absorption performance, and a reflection loss of -57.13 dB was achieved at 3.98 mm. Further study revealed that the optimized impedance matching and large attenuation constant were conducive to a good absorption performance. Meanwhile, the combined action of dielectric loss and magnetic loss was responsible for the electromagnetic wave attenuation. This study provides a supplementary approach to microwave absorption materials with a desirable absorption performance.

scholarly journals Preparation and electromagnetic properties characterization of reduced graphene oxide/strontium hexaferrite nanocomposites

2020 ◽  
Vol 9 (1) ◽  
pp. 105-114 ◽  
Author(s):  
Shumin Du ◽  
Huaiyin Chen ◽  
Ruoyu Hong
Keyword(s):  
Electromagnetic Wave ◽  
Environmental Pollution ◽  
Electromagnetic Interference ◽  
Electromagnetic Waves ◽  
Rapid Development ◽  
Living Environment ◽  
World Health ◽  
Electromagnetic Properties ◽  
Strontium Hexaferrite ◽  
Wave Radiation

AbstractWith the rapid development of electronics and information technology, electronics and electrical equipment have been widely used in our daily lives. The living environment is full of electromagnetic waves of various frequencies and energy. Electromagnetic wave radiation has evolved into a new type of environmental pollution that has been listed by the WHO (World Health Organization) as the fourth largest source of environmental pollution after water, atmosphere, and noise. Studies have shown that when electromagnetic wave radiation is too much, it can cause neurological disorders. And electromagnetic interference will cause the abnormal operation of medical equipment, precision instruments and other equipment, and therefore cause incalculable consequences. Therefore, electromagnetic protection has become a hot issue of concern to the social and scientific circles.

scholarly journals Structural Engineering of Hierarchical Aerogels Comprised of Multi-dimensional Gradient Carbon Nanoarchitectures for Highly Efficient Microwave Absorption

2021 ◽  
Vol 13 (1) ◽  
Author(s):  
Yongpeng Zhao ◽  
Xueqing Zuo ◽  
Yuan Guo ◽  
Hui Huang ◽  
Hao Zhang ◽  
...  
Keyword(s):  
Microwave Absorption ◽  
Structural Engineering ◽  
Carbon Nanomaterials ◽  
Wave Attenuation ◽  
Impedance Matching ◽  
Chemical Vapor ◽  
Electromagnetic Properties ◽  
Effective Bandwidth ◽  
Carbon Aerogels ◽  
Chemical Vapor Deposition Method

AbstractRecently, multilevel structural carbon aerogels are deemed as attractive candidates for microwave absorbing materials. Nevertheless, excessive stack and agglomeration for low-dimension carbon nanomaterials inducing impedance mismatch are significant challenges. Herein, the delicate “3D helix–2D sheet–1D fiber–0D dot” hierarchical aerogels have been successfully synthesized, for the first time, by sequential processes of hydrothermal self-assembly and in-situ chemical vapor deposition method. Particularly, the graphene sheets are uniformly intercalated by 3D helical carbon nanocoils, which give a feasible solution to the mentioned problem and endows the as-obtained aerogel with abundant porous structures and better dielectric properties. Moreover, by adjusting the content of 0D core–shell structured particles and the parameters for growth of the 1D carbon nanofibers, tunable electromagnetic properties and excellent impedance matching are achieved, which plays a vital role in the microwave absorption performance. As expected, the optimized aerogels harvest excellent performance, including broad effective bandwidth and strong reflection loss at low filling ratio and thin thickness. This work gives valuable guidance and inspiration for the design of hierarchical materials comprised of dimensional gradient structures, which holds great application potential for electromagnetic wave attenuation. "Image missing"

scholarly journals Microstructure and Electromagnetic Properties of Ni-Zn-Co Ferrite up to 20 GHz

2016 ◽  
Vol 2016 ◽  
pp. 1-7 ◽  
Author(s):  
Charalampos Stergiou
Keyword(s):  
Wall Motion ◽  
Wave Attenuation ◽  
Domain Wall Motion ◽  
Electromagnetic Properties ◽  
Complex Permeability ◽  
Microwave Dielectric ◽  
Zn Ferrite ◽  
Spin Resonance ◽  
Production Stages

The present paper examines the relation between different developed microstructures and the microwave electromagnetic properties in Ni-Zn-Co ferrite. To this end, the Ni0.25Zn0.25Co0.5Fe2O4composition has been prepared with the conventional ceramic process with varied prefiringTP(750°C, 1000°C) and sinteringTStop temperatures (1200°C, 1250°C). When lower temperatures are applied in these production stages, incomplete microstructures with low density, higher porosity, or finer grains are achieved. On account of these features, the contributions of domain wall motion and spin rotation to the complex permeabilityμ⁎(f)move to higher frequencies, whereas microwave dielectric permittivityε⁎(f)is decreased. In particular in conjunction with the high Co content, the wall relaxation and spin resonance are interestingly forced to occur at 850 MHz and 8.05 GHz, respectively. Regarding the electromagnetic wave attenuation, the ferrite annealed at lower temperatures exhibits strong return loss peaks at higher frequencies, but without other performance improvement. We should notice that the variations in sintering temperatureTSyield the maximum changes in the recorded parameters, including the coercive field,μ⁎(f),andε⁎(f), indicating the inferior role of prefiringTPin Ni-Zn ferrite.

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