Effect of the cobalt ferrite and carbon fiber powder doping ratio on the electromagnetic properties of coated polyaniline-based polyester–cotton fabric

2021 ◽  
pp. 004051752110608
Author(s):  
Yi Wang ◽  
Yuanjun Liu ◽  
Chao Yang ◽  
Xiaoming Zhao
Keyword(s):  
Dielectric Constant ◽  
Carbon Fiber ◽  
Cotton Fabric ◽  
Imaginary Part ◽  
Reflection Loss ◽  
Cobalt Ferrite ◽  
Electromagnetic Properties ◽  
Loss Angle ◽  
The Real ◽  
Doping Ratio

In this project, firstly, polyaniline-based polyester–cotton fabric was prepared by in situ polymerization using polyester–cotton fabric as the base fabric, aniline as the monomer, ammonium persulfate as the oxidizer, and camphor sulfonic acid as the dopant. Secondly, cobalt ferrite/carbon fiber powder-coated polyaniline-based polyester–cotton fabric was prepared by the textile coating process using polyaniline-based polyester–cotton fabric as the base fabric, PU2540-type polyurethane as the adhesive, and cobalt ferrite and carbon fiber powder as functional particles. Finally, the effect of the cobalt ferrite and carbon fiber powder doping ratio on the shielding effectiveness, reflection loss, dielectric constant real part, imaginary part, and loss angle tangent of cobalt ferrite/carbon fiber powder-coated polyaniline-based polyester–cotton fabric was studied by using the controlled variable method with emphasis on the cobalt ferrite/carbon fiber powder doping ratio. The results show that in the frequency range of 0.01–3.0 GHz, when the doping ratio of cobalt ferrite to carbon fiber powder is 0:3, the reflection loss of cobalt ferrite/carbon fiber powder-coated polyaniline-based polyester–cotton fabric reaches the minimum value at 1.49 GHz, the minimum reflection loss is –21.4 dB, and the effective absorption band is 1.25–1.94 GHz. In the test band, the shielding efficiency, reflection loss, the real part and imaginary part of the dielectric constant, and the loss angle tangent of the carbon fiber powder-coated polyaniline-based polyester–cotton fabric are larger than those of cobalt ferrite-coated polyaniline-based polyester–cotton fabric. The smaller the doping ratio of cobalt ferrite to carbon fiber powder, the larger value of the shielding efficiency, reflection loss, the real part and imaginary part of the dielectric constant, and loss angle tangent of the cobalt ferrite/carbon fiber powder-coated polyaniline-based polyester–cotton fabric.

scholarly journals Infrared Absorption and Reflection Spectra of Crystalline TCNQ Salts

1989 ◽  
Vol 42 (2) ◽  
pp. 203 ◽  
Author(s):  
Ajay T Oza
Keyword(s):  
Dielectric Constant ◽  
Imaginary Part ◽  
Infrared Absorption ◽  
Reflectance Spectra ◽  
Reflection Spectra ◽  
Reflectance Curve ◽  
The Real ◽  
Broad Maximum ◽  
Absorption Features ◽  
Reflection Characteristics

The polarised absorption and reflectance spectra of the three TCNQ salts pyridinium (TCNQh, triethylammonium (TCNQh and thermally damaged quinolinium (TCNQh indicate that the absorption features are governed by reflection characteristics. The maximum reflectance curve shows a broad minimum which corresponds to a negative dip in the real part of the dielectric constant and a broad maximum in the imaginary part, as calculated using a Kramers-Kronig

Preparation of poly-p-phenylenebenzobisoxazole (PBO) fibrillated pulp and dielectric properties of carbon fiber/PBO wet-laid nonwoven fabric

2017 ◽  
Vol 88 (13) ◽  
pp. 1559-1568 ◽  
Author(s):  
Jingjing Bai ◽  
Hao Wang ◽  
Yi Wang ◽  
Jian Hu
Keyword(s):  
Dielectric Properties ◽  
Carbon Fiber ◽  
Mechanical Strength ◽  
Reflection Loss ◽  
Complex Permittivity ◽  
Nonwoven Fabric ◽  
Electromagnetic Properties ◽  
Optimum Thickness ◽  
Permittivity And Permeability ◽  
Different Content

A method to prepare a kind of wet-laid nonwoven fabric that can be used in microwave absorbing honeycomb is proposed. It was prepared through a papermaking process with carbon fiber (CF) and poly-p-phenylenebenzobisoxazole (PBO) fibrillated pulp. Fibrillated PBO pulp has a large surface area and lots of micro-fibrils which is beneficial for the uniformity and mechanical strength of the wet-laid nonwoven fabric. The electromagnetic properties and absorbing performances of the wet-laid nonwoven fabric with different content of CF were compared. The results showed that the complex permittivity increased when the content of the CF increased, and then decreased when the content was higher than 10 wt%. The resistivity measured by four probe testers decreased with the increase of the content of CF. Calculated by the measured complex permittivity and permeability, the CF/PBO wet-laid nonwoven fabric had a lowest reflection loss of -27.60 dB at a content of 20 wt%, with an optimum thickness of 1.72 mm.

Effect of Li2O-Al2O3-Bi2O3-SiO2 Glass on Electromagnetic Properties of Ni0.16Cu0.22Zn0.62Fe2O4-BaTiO3 Composites at Low Sintering Temperature

2019 ◽  
Vol 960 ◽  
pp. 250-255
Author(s):  
Qiang Zhao ◽  
Huai Wu Zhang ◽  
Jie Li
Keyword(s):  
Dielectric Constant ◽  
Saturation Magnetization ◽  
Sintering Temperature ◽  
Solid State Reaction Method ◽  
Glass Content ◽  
Electromagnetic Properties ◽  
Magnetic And Dielectric Properties ◽  
Tan Δ ◽  
Quality Factor Q ◽  
Doping Ratio

In the present work, the composite material Ni0.16Cu0.22Zn0.62Fe2O4-BaTiO3 (NCZF-BTO, in a 10:1) was synthesized with different additive amounts of Li2O-Al2O3-Bi2O3-SiO2 (LABS) glass using a traditional solid-state reaction method and sintered at 900 °C. The synthesized composites were then comparatively investigated; in addition to their phases and density, their magnetic and dielectric properties, which include the saturation magnetization(4πMs), coercivity (Hc), permeability (μ'), quality factor (Q), dielectric constant (ε')and dielectric loss (tan δ) were characterized. In contrast to the undoped composites, the performance of the LABS-doped samples were enhanced. The optimal performance was obtained when the LABS glass content reached 1.0wt%. At this level of doping, the bulk density increased from 4.883 g/cm3 to 5.021g/cm3, the saturation magnetization (4πMs) increased from 3819.5 to 4113.6Gs, the coercivity (Hc) decreased from 111 to 106.5A/m, the permeability (μ') at 10 MHz increased from 25.8 to 61.1, and the dielectric constant (ε') at 10 MHz increased from 18.9 to 23.4. On further increasing the LABS glass content to1.5 wt%, the performance of the composite generally deteriorated, except for the dielectric constant,which increased to 27.1. In short, the optimal LABS glass doping ratio was determined to be 1.0 wt%.

Electromagnetic Wave Absorption Behavior of NiZn-Ferrite Prepared via Hydrothermal Method

2005 ◽  
Vol 480-481 ◽  
pp. 595-602 ◽  
Author(s):  
Cheng-Hsiung Peng ◽  
Hong-Wen Wang ◽  
Shih-Wei Kan ◽  
San-Yuan Chen
Keyword(s):  
Electromagnetic Wave ◽  
Hydrothermal Method ◽  
Imaginary Part ◽  
Reflection Loss ◽  
Effective Medium Theory ◽  
Frequency Range ◽  
Medium Theory ◽  
Electromagnetic Wave Absorption ◽  
The Real ◽  
Effect Of Particle Size

Ni0.5Zn0.5Fe2O4 ferrite powders were synthesized by a hydrothermal method. The nanoparticles of these materials were mixed with a thermal-plastic polyurethane (TPU)polymer in order to form a suitable composite for electromagnetic wave absorber in a frequency range from 2.0 to 15.0 GHz. The effect of particle size on the reflection loss was investigated by comparing nanosized and microsized powders. The reflection loss as a function of frequency ( f ), thickness of the absorber(d), the real and imaginary part of permittivity (ε’ /ε”) and the real and imaginary part of permeability (μ’/μ”) were obtained by calculation using the Bruggeman effective medium theory. The effect of Co2+, Cu2+, and Mg2+ on the reflection loss was also studied.

scholarly journals Determination of the complex dielectric permeability of liquid at the radiation frequency 32 GHz

2021 ◽  
Vol 1198 (1) ◽  
pp. 012012
Author(s):  
B G Tsydypov ◽  
A V Bazarov ◽  
B V Basanov ◽  
B Z Garmaev ◽  
E Yu Korovin ◽  
...  
Keyword(s):  
Dielectric Constant ◽  
Reflection Coefficient ◽  
Imaginary Part ◽  
Dielectric Permeability ◽  
Complex Dielectric Constant ◽  
Radiation Frequency ◽  
Layer Depth ◽  
The Real

Abstract Method and device for measuring the complex dielectric constant of liquids are described. The real part of the complex dielectric constant calculated from the conditions for the maximum and minimum of the measured interference dependence of the reflection coefficient on the layer depth. The imaginary part determined by selection to the maximum coincidence of the calculated and measured dependences of the reflection coefficient.

A WAVE-GUIDE METHOD OF MEASUREMENT OF THE DIELECTRIC CONSTANT OF LOW-LOSS LIQUIDS

1963 ◽  
Vol 41 (8) ◽  
pp. 1314-1320 ◽  
Author(s):  
I. R. Dagg ◽  
G. E. Reesor
Keyword(s):  
Dielectric Constant ◽  
Carbon Tetrachloride ◽  
Imaginary Part ◽  
Wave Guide ◽  
Impedance Change ◽  
Frequency Range ◽  
Low Loss ◽  
Dielectric Interface ◽  
The Real ◽  
Method Of Measurement

A method of measurement of the real and imaginary parts of the dielectric constant of low-loss liquids is described. The real part of the dielectric constant is derived from the impedance change at an air–dielectric interface in a wave guide; the imaginary part is derived from attenuation measurements made on a liquid-filled guide. The results of initial measurements on carbon tetrachloride and heptane in the frequency range 8.2 to 12.4 Gc/s are given.

Enhanced performance of supercapacitors by constructing a “mini parallel-plate capacitor” in an electrode with high dielectric constant materials

2020 ◽  
Vol 8 (32) ◽  
pp. 16661-16668
Author(s):  
Huayao Tu ◽  
Shouzhi Wang ◽  
Hehe Jiang ◽  
Zhenyan Liang ◽  
Dong Shi ◽  
...  
Keyword(s):  
Dielectric Constant ◽  
Carbon Fiber ◽  
Parallel Plate ◽  
Sandwich Structure ◽  
High Dielectric Constant ◽  
Parallel Plate Capacitor ◽  
Plate Capacitor ◽  
Fiber Metal ◽  
High Dielectric ◽  
Mini Plate

The carbon fiber/metal oxide/metal oxynitride layer sandwich structure is constructed in the electrode to form a mini-plate capacitor. High dielectric constant metal oxides act as dielectric to increase their capacitance.

A study on the electromagnetic properties of graphite/bismuth/bismuth oxide-coated composites

2021 ◽  
pp. 004051752199434
Author(s):  
Yuanjun Liu ◽  
Yanfeng Yang
Keyword(s):  
Mechanical Property ◽  
Dielectric Constant ◽  
Bismuth Oxide ◽  
Control Variable ◽  
Single Layer ◽  
Polarization Property ◽  
Electromagnetic Properties ◽  
Shielding Effectiveness ◽  
Absorbing Property ◽  
Layer Coating

Coating is a commonly used process for the preparation of protective textiles. In this study, the absorbing coated composite material was prepared by a coating process, using plain weave polyester/cotton fabric as the base fabric, PU-2540 polyurethane as the binder, and graphite, bismuth and bismuth oxide as the functional particles. The effects of the content of functional particles and the ratio of functional particles on the dielectric constant, reflection loss, shielding effectiveness, and tensile strength of the single-layer coating composites were studied using the control variable method. The results showed that when the frequency was 1–1000 MHz, the real and imaginary parts of the dielectric constant, the tangential value of the loss angle, and the tensile value increased with the increase of the coating content, and the polarization, loss and attenuation property, and mechanical property of the electromagnetic wave were enhanced. When graphite, bismuth, and bismuth oxide was mixed at the ratio of 9:0:0 in weight, the polarization property was the best. When mixed at the ratio of 6:1:2 in weight, the loss performance and attenuation ability were the best. When mixed at the ratio of 6:3:0 in weight, the absorbing property and mechanical property were the best. When mixed at the ratio of 6:2:1 in weight, the shielding property was the best.

The Hertzian Spectrum of Rubber and Its Micellar Constitution

1946 ◽  
Vol 19 (4) ◽  
pp. 1085-1087
Author(s):  
Pierre Girard ◽  
Paul Abadie
Keyword(s):  
Dielectric Constant ◽  
Electric Field ◽  
Wave Length ◽  
Structural Features ◽  
Loss Angle ◽  
First Case ◽  
Dipolar Molecules ◽  
Alternating Electric Field ◽  
Different Types ◽  
Absorption And Dispersion

Abstract The spectra which were studied lie within the region of hertzian frequencies, and can be represented either by dispersion curves showing the dielectric constant of the substance as a function of the frequency (or wave length λ), or by absorption curves showing the loss angle as a function of this frequency. These two types of curves represent the same phenomenon, i.e., orientation of the dipolar molecules in the alternating electric field, in accordance with the theory of Debye. The spectra and their interpretation depend chiefly on whether the molecules are crystalloid with relatively small and similar dimensions, or are colloidal, with large and unequal dimensions. In the first case, the spectra gives evidence chiefly on the form of the molecules and their structural features. Dilution in a nonpolar solvent shows for certain dipolar compounds, e.g., alcohol, considerable deformations, which differ according to the solvent. In the case of colloids, e.g., rubber, which has a permanent moment, the spectra and the meaning of these spectra are far different. In this case the spectra indicate that the absorption and dispersion values in the hertzian region are closely related to the micellar constitution, i.e., to the different types of micelles, to their size, and to the proportion of each type.

Preparation and Electromagnetic Properties of Al2O3/Ni Composites

2014 ◽  
Vol 602-603 ◽  
pp. 926-930
Author(s):  
Zhi Xue Qu ◽  
Qun Wang ◽  
Bin Pang ◽  
Xue Cheng Hou ◽  
Wei Pan
Keyword(s):  
Dielectric Constant ◽  
Electromagnetic Compatibility ◽  
Sintering Temperature ◽  
Substrate Material ◽  
Electromagnetic Properties ◽  
Ni Content

In this paper, a series of Al2O3/Ni composites with various content of Ni (0 vol%, 10 vol%, 20 vol%, 30 vol%, 40 vol% and 50 vol%) were prepared, and the effect of the methods and compositions on the density and electromagnetic properties was investigated. The results show that the density of the composites increases with the increasing sintering temperature as well as the increasing content of Ni. Moreover, the dielectric constant of the composites increases remarkably with the sintering temperature and the content of Ni, while the permeability shows an almost linear enhancement with the increase of Ni content. This suggests that the Al2O3/Ni composite can be expected to be a promising substrate material with certain electromagnetic compatibility.

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