scholarly journals Preparation and electromagnetic wave absorbing properties of 3D graphene/pine needle-like iron nano-acicular whisker composites

RSC Advances ◽  
2017 ◽  
Vol 7 (26) ◽  
pp. 16196-16203 ◽  
Author(s):  
Tingkai Zhao ◽  
Wenbo Jin ◽  
Xianglin Ji ◽  
Junjie Gao ◽  
Chuanyin Xiong ◽  
...  
Keyword(s):  
Electromagnetic Wave ◽  
Reflection Loss ◽  
Frequency Bandwidth ◽  
Pine Needle ◽  
Electromagnetic Wave Absorption ◽  
3D Graphene ◽  
Wave Absorption ◽  
High Reflection

The improvement of high reflection loss and broad frequency bandwidth for electromagnetic wave absorption materials is a long-term effort.

Electromagnetic Wave Absorption Cement Based on Composited Absorbing Agent

2014 ◽  
Vol 1035 ◽  
pp. 520-523 ◽  
Author(s):  
Ye Sun ◽  
Yue Fang Zhang ◽  
Wan Jun Hao
Keyword(s):  
Electromagnetic Wave ◽  
Carbon Black ◽  
Electromagnetic Radiation ◽  
Glass Fiber ◽  
Radiation Protection ◽  
Reflection Loss ◽  
Absorption Properties ◽  
Electromagnetic Wave Absorption ◽  
Wave Absorption ◽  
Electromagnetic Radiations

To solve more and more serious electromagnetic radiations, electromagnetic wave absorption cement were prepared by introducing carbon black and glass fiber as composited absorbing reagent, wich can be useful in building anechoic chamber and other electromagnetic radiation protection to buildings. The results showed that the absorption properties were improved compared with single absorbing agent such as carbon or glass fiber. the lowest reflection loss of-11.3dB was obtained at 18 GHz of 5wt.% carbon black and 9wt.% glass fiber filled cement with thickness of 20mm. The increase of thickness separately can not improve the absorption properties.

scholarly journals Spawns Structure of Rod-Like ZnO Wrapped in Cellulose Nanofibers for Electromagnetic Wave Absorption

2017 ◽  
Vol 2017 ◽  
pp. 1-6
Author(s):  
Bitao Fan ◽  
Qiufang Yao ◽  
Chao Wang ◽  
Ye Xiong ◽  
Qingfeng Sun ◽  
...  
Keyword(s):  
Electromagnetic Wave ◽  
Reflection Loss ◽  
Cellulose Nanofibers ◽  
Absorption Properties ◽  
Composite Aerogel ◽  
Electromagnetic Wave Absorption ◽  
Wave Absorption ◽  
One Step ◽  
Absorption Performance ◽  
Minimum Reflection Loss

Spawns structure of rod-like ZnO wrapped in the cellulose nanofibers was successfully fabricated through a facile one-step hydrothermal method, and their electromagnetic wave absorption properties were investigated. The structure and properties of the composite aerogel were characterized. The enlarged morphology images showed that the as-prepared cellulose nanofiber/ZnO samples were spawns structure of rod-like ZnO wrapped in the cellulose nanofibers. The composite aerogel in a wax matrix exhibited excellent electromagnetic wave absorption performance over 2–18 GHz. The widest absorption bandwidth of 30 wt% contained with reflection loss values less than −10 dB was up to 12 GHz (6–18 GHz) at the thickness of 5.5 mm and the minimum reflection loss value reached −26.32 dB at 15.2 GHz when the thickness of the absorber was 3 mm.

scholarly journals PENGARUH SUBSTITUSI ION Ti-Zn TERHADAP SIFAT KEMAGNETAN dan SIFAT PENYERAPAN GELOMBANG ELEKTROMAGNETIK MATERIAL SISTEM BaFe12-xTix/2Znx/2O19

2017 ◽  
Vol 2 (2) ◽  
pp. 99 ◽  
Author(s):  
Nenni Nenni ◽  
Mutia Delina ◽  
Wisnu Ari Adi ◽  
Yana Taryana
Keyword(s):  
Magnetic Material ◽  
Electromagnetic Wave ◽  
Reflection Loss ◽  
Doping Concentration ◽  
Hysteresis Curve ◽  
Wet Milling ◽  
X Ray Diffraction ◽  
Electromagnetic Wave Absorption ◽  
Wave Absorption ◽  
Milling Method

Substitution of Ti+4 and Zn+2 ions on magnetic material BaFe12-xTix/2Znx/2O19 (x = 0 and 2) using the wet milling method has been performed. This research was conducted to get information the influence of Ti-Zn substitution on magnetic properties and its absorption. The magnetic material BaFe12-xTix/2Znx/2O19 is synthesized from a mixture of oxide materials, BaCO3, Fe2O3, TiO2 and ZnO. The mixture was milled for 5 hours, dried at 1000C then sintered at 10000C for 5 hours. The refinement result of the X-ray diffraction pattern shows that the sample has single phase BaFe12O19 with doping concentration of x = 0 and 2. The hysteresis curve shows that coercivity field value decreased in the sample with doping concentration of x = 2. The result of electromagnetic wave absorption shows that the substituted sample with Ti+4 and Zn+2 ions (doping concentration x = 2) has the highest absorption peak at a frequency of 11,2 GHz with reflection loss value (RL) of -24,3 dB. Electromagnetic wave absorption reaches 94% with sample thickness is about 1,0 mm. Therefore, the magnetic material BaFe12-xTix/2Znx/2O19 (x = 2) can be used for application of the electromagnetic wave absorber. Keywords: Substitution, BaFe12-xTix/2Znx/2O19, wet milling, reflection loss, electromagnetic wave absorber.

scholarly journals In situ synthesis and electromagnetic wave absorbing properties of sandwich microstructured graphene/La-doped barium ferrite nanocomposite

RSC Advances ◽  
2017 ◽  
Vol 7 (59) ◽  
pp. 37276-37285 ◽  
Author(s):  
Tingkai Zhao ◽  
Wenbo Jin ◽  
Yixue Wang ◽  
Xianglin Ji ◽  
Huibo Yan ◽  
...  
Keyword(s):  
Electromagnetic Wave ◽  
Reflection Loss ◽  
Barium Ferrite ◽  
In Situ Synthesis ◽  
Frequency Bandwidth ◽  
Absorbing Materials ◽  
Long Time ◽  
La Doped ◽  
High Reflection

The development of high reflection loss and broad frequency bandwidth for electromagnetic wave absorbing materials has been pursued for a long time.

Design and Optimize Spherical Particle Absorber for Broadband Electromagnetic Wave Absorption Wall

2010 ◽  
Vol 143-144 ◽  
pp. 1051-1055
Author(s):  
Zhang Hong Tang ◽  
Wang Qun
Keyword(s):  
Electromagnetic Wave ◽  
Spherical Particle ◽  
Reflection Loss ◽  
Electromagnetic Wave Absorption ◽  
Wave Absorption ◽  
Simulation Results ◽  
Maximum Reflection Loss

In this paper, a method to simulate the absorbing effectiveness of spherical particle absorber is presented and the effect of the diameter of spheres, the number of layer and the stack modes of sphere particle to the absorbing effectiveness were also researched. Basing on the simulation results, an optimal spherical particle absorber was designed. The absorber has 3 layers with 1 mm, 2 mm and 4 mm spheres stacked on each layer respectively. Simulation result shows that the optimal absorber achieves a maximum reflection loss of -15 dB and the bandwidth being lower than -5 dB is more than 16 GHz in 1~18 GHz.

scholarly journals Nickel Carbon Composite With Carbon Nanotubes for Efficient Electromagnetic Wave Absorption

2020 ◽  
Author(s):  
Yun Qiu ◽  
Haibo Yang ◽  
Liang Ma ◽  
Ying Lin ◽  
Hanwen Zong ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Electromagnetic Wave ◽  
Reflection Loss ◽  
Carbon Composite ◽  
Hybrid Network ◽  
Hierarchical Architecture ◽  
Mass Ratio ◽  
Electromagnetic Wave Absorption ◽  
Wave Absorption ◽  
Metal Organic

Abstract Nickel carbon composite with carbon nanotubes (Ni-C/CNTs) has been fabricated by pyrolysis the mixture of nickel-based metal organic framework (Ni-MOF) and melamine. The resultant Ni-C/CNTs composite is assembled from one-dimensional (1D) CNTs and three dimensional (3D) spherical Ni-C composite. Besides, the Ni-C/CNTs composite contains abundant nitrogen(N) dopants that contributes to defect dipole polarization. The diameter and length of CNTscan beeffected by changing the mass ratio of Ni-MOF and melamine. The optimizedNi-C/CNTs composite exhibits reflection loss of -55.1 dB at 10.56 GHz, and the effective absorbing bandwidth (reflection loss < -10 dB) is 11.2 GHz (6.0-17.2 GHz)with the thickness range of 1.5-4.0 mm, when the mass ratio of Ni-MOF: melamine is 1: 2. These results indicate that the mixed 1D-3D hierarchical architecture synergistically improves electromagnetic wave absorption properties. This strategy willcontribute for fabricating the carbon hybrid network consisting of metal organic frameworks derived metal/carbon hybrid and CNTs for electromagnetic wave absorption.

Broadband Micro-Wave Absorption Properties of Ni-P Coated Fe Nanoparticles by Electroless Plating Process

2012 ◽  
Vol 549 ◽  
pp. 665-669 ◽  
Author(s):  
Gui Mei Shi ◽  
Wei Min Sun ◽  
Da Wei Lu ◽  
Shu Lian
Keyword(s):  
Electromagnetic Wave ◽  
Layer Thickness ◽  
Reflection Loss ◽  
Electroless Plating ◽  
Coating Layer ◽  
Absorption Properties ◽  
Electromagnetic Wave Absorption ◽  
Wave Absorption ◽  
Absorption Layer ◽  
Fe Nanoparticles

Fe nanoparticles with shell of Ni-P coating layer were successfully synthesized using Ni electroless plating process. Electromagnetic-wave absorption of Ni-P coated Fe nanoparticles has been investigated. In contrast to earlier reported materials, the absorption amplitude of as-prepared samples is found not largely decrease with increasing absorption-layer thickness. A reflection loss (RL) exceeding -20 dB can be obtained for almost the whole frequencies within the 2-18GHz range by choosing an appropriate layer thickness between 0.9 and 6.0mm. The broadest bandwidth (RLu-bands(12-18GHz), is obtained for 1.1mm layer. At the same time, it is worth noticing that in a thin thickness range 0.91-2.0mm, the reflection loss (RL) exceeding -10 dB in the 6-18GHz range is obtained, which covers half of C-bands (4-8GHz), the whole X-bands (8-12GHz) and Ku–bands (12-18GHz).

Fabrication of multi-functional PVDF/RGO composites via a simple thermal reduction process and their enhanced electromagnetic wave absorption and dielectric properties

RSC Advances ◽  
2014 ◽  
Vol 4 (38) ◽  
pp. 19594-19601 ◽  
Author(s):  
Xiao-Juan Zhang ◽  
Guang-Sheng Wang ◽  
Wen-Qiang Cao ◽  
Yun-Zhao Wei ◽  
Mao-Sheng Cao ◽  
...  
Keyword(s):  
Electromagnetic Wave ◽  
Dielectric Properties ◽  
Reflection Loss ◽  
Reduction Process ◽  
Thermal Reduction ◽  
Filler Loading ◽  
Electromagnetic Wave Absorption ◽  
Wave Absorption

The PVDF/RGO composites synthesized by a thermal reduction process exhibit high values of reflection loss and excellent dielectric properties with low filler loading.

scholarly journals Enhanced Electromagnetic Wave Absorption Properties of Ultrathin MnO2 Nanosheet-Decorated Spherical Flower-Shaped Carbonyl Iron Powder

Molecules ◽  
2021 ◽  
Vol 27 (1) ◽  
pp. 135
Author(s):  
Zhengwei Qu ◽  
Yi Wang ◽  
Pingan Yang ◽  
Wei Zheng ◽  
Nan Li ◽  
...  
Keyword(s):  
Electromagnetic Wave ◽  
Iron Powder ◽  
Oxidation Resistance ◽  
Reflection Loss ◽  
Carbonyl Iron ◽  
Absorption Properties ◽  
Absorption Bandwidth ◽  
Electromagnetic Wave Absorption ◽  
Wave Absorption ◽  
Minimum Reflection Loss

In this work, spherical flower-shaped composite carbonyl iron powder@MnO2 (CIP@MnO2) with CIP as the core and ultrathin MnO2 nanosheets as the shell was successfully prepared by a simple redox reaction to improve oxidation resistance and electromagnetic wave absorption properties. The microwave-absorbing properties of CIP@MnO2 composites with different filling ratios (mass fractions of 20%, 40%, and 60% after mixing with paraffin) were tested and analyzed. The experimental results show that compared with pure CIP, the CIP@MnO2 composites have smaller minimum reflection loss and a wider effective absorption bandwidth than CIP (RL < −20 dB). The sample filled with 40 wt% has the best comprehensive performance, the minimum reflection loss is −63.87 dB at 6.32 GHz, and the effective absorption bandwidth (RL < −20 dB) reaches 7.28 GHz in the range of 5.92 GHz–9.28 GHz and 11.2 GHz–15.12 GHz, which covers most C and X bands. Such excellent microwave absorption performance of the spherical flower-like CIP@MnO2 composites is attributed to the combined effect of multiple beneficial components and the electromagnetic attenuation ability generated by the special spherical flower-like structure. Furthermore, this spherical flower-like core–shell shape aids in the creation of discontinuous networks, which improve microwave incidence dispersion, polarize more interfacial charges, and allow electromagnetic wave absorption. In theory, this research could lead to a simple and efficient process for producing spherical flower-shaped CIP@MnO2 composites with high absorption, a wide band, and oxidation resistance for a wide range of applications.

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