scholarly journals Electromagnetic Properties of Hexagonal Ferrite in the Frequency Range of 1 to 20GHz. Application of Y-Type Ferrite to Electromagnetic Wave Absorber.

1999 ◽  
Vol 46 (1) ◽  
pp. 88-91 ◽  
Author(s):  
Kiichi Oda ◽  
Tetsuji Inui
Keyword(s):  
Electromagnetic Wave ◽  
Hexagonal Ferrite ◽  
Electromagnetic Properties ◽  
Frequency Range

Electromagnetic Properties of Bearing Cement-Based Materials

2011 ◽  
Vol 261-263 ◽  
pp. 663-668
Author(s):  
Ai Li Guo ◽  
Ri Gao ◽  
Heng Jing Ba
Keyword(s):  
Electromagnetic Wave ◽  
Electromagnetic Waves ◽  
Building Materials ◽  
Incident Angle ◽  
High Strength ◽  
Wave Incident ◽  
Electromagnetic Properties ◽  
Frequency Range ◽  
Electromagnetic Wave Incident ◽  
Cement Based Materials

For studying absorption/bearing integration of building materials, high-strength cement-based materials were prepared by using active fly ash, silica fume and quartz, etc. Electromagnetic parameters of the cement-based materials were measured through coaxial method, and then by means of these parameters, the reflectivity of electromagnetic waves of the cement-based materials were simulated under variable electromagnetic wave incident angle (θ), frequency (f) and thickness of the material(d).The reflectivity of electromagnetic waves with 8~18GHz frequency range vertically transmitting into the cement-based materials was obtained through far field radar scattered cross-section measurement, and was compared with simulated reflectance under the same incident conditions. The results show that the high-strength cement-based materials with imaginary part of dielectric constant can consume energy of the incident electromagnetic wave. Incident angle less than 15° has little effect on the reflectivity of the cement-based materials in 2~18GHz frequency range. While the thickness of the cement-based materials is 15mm or 25mm, simulation results of the reflectivity are in good agreement with measured ones. Measured absorption peak and -10dB bandwidth increase with the increasing of thickness of the cement-based materials with compressive strength of 120.7MPa. This suggests that the cement-based materials studied in this paper have the characteristics of absorption/bearing integration.

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.

Electromagnetic Wave Absorbing and Mechanical Properties of Cement-Based Composite Panel with Different Nanomaterials

2017 ◽  
Vol 26 (1) ◽  
pp. 096369351702600
Author(s):  
Sun Yafei ◽  
Gao Peiwei ◽  
Peng Hailong ◽  
Liu Hongwei ◽  
Lu Xiaolin ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Electromagnetic Wave ◽  
Double Layer ◽  
Mechanical Performance ◽  
Interface Structure ◽  
Composite Panel ◽  
Effective Bandwidth ◽  
Composite Panels ◽  
Frequency Range ◽  
Triple Layer

This paper presents the microstructures and mechanical and absorbing properties of double and triple layer, cement-based, composite panels. The results obtained show that the frequency range in 2-18GHz had less than −10dB effective bandwidth, which correlates with 3.7and 10.8GHz in double and triple layer cement-based composite panels. Furthermore, the double layer panel's compressive strength at 7 and 28 days was 40.2 and 61.2MPa, respectively. For the triple layer panel, the strength values were 35.6MPa and 49.2MPa. The triple layer panel's electromagnetic wave (EMW) absorbing properties were superior compared to the properties of the double layer panel. However, the triple layer panel's mechanical performance was inferior to that of the double layer panel. This study proposes that carbon nanotubes can effectively improve the compressive strength and interface structure of cement-based composite panels.

scholarly journals Modelling natural electromagnetic interference in man-made conductors for space weather applications

2016 ◽  
Vol 34 (4) ◽  
pp. 427-436 ◽  
Author(s):  
Larisa Trichtchenko
Keyword(s):  
Exact Solution ◽  
Space Weather ◽  
Electromagnetic Interference ◽  
Geomagnetic Storms ◽  
Electromagnetic Properties ◽  
Electromagnetic Response ◽  
Frequency Range ◽  
Geomagnetically Induced Currents ◽  
Geomagnetic Variations ◽  
Wide Range

Abstract. Power transmission lines above the ground, cables and pipelines in the ground and under the sea, and in general all man-made long grounded conductors are exposed to the variations of the natural electromagnetic field. The resulting currents in the networks (commonly named geomagnetically induced currents, GIC), are produced by the conductive and/or inductive coupling and can compromise or even disrupt system operations and, in extreme cases, cause power blackouts, railway signalling mis-operation, or interfere with pipeline corrosion protection systems. To properly model the GIC in order to mitigate their impacts it is necessary to know the frequency dependence of the response of these systems to the geomagnetic variations which naturally span a wide frequency range. For that, the general equations of the electromagnetic induction in a multi-layered infinitely long cylinder (representing cable, power line wire, rail or pipeline) embedded in uniform media have been solved utilising methods widely used in geophysics. The derived electromagnetic fields and currents include the effects of the electromagnetic properties of each layer and of the different types of the surrounding media. This exact solution then has been used to examine the electromagnetic response of particular samples of long conducting structures to the external electromagnetic wave for a wide range of frequencies. Because the exact solution has a rather complicated structure, simple approximate analytical formulas have been proposed, analysed and compared with the results from the exact model. These approximate formulas show good coincidence in the frequency range spanning from geomagnetic storms (less than mHz) to pulsations (mHz to Hz) to atmospherics (kHz) and above, and can be recommended for use in space weather applications.

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.

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