scholarly journals Interaction of electromagnetic radiation in the 20–200 GHz frequency range with arrays of carbon nanotubes with ferromagnetic nanoparticles

2015 ◽  
Vol 6 ◽  
pp. 1056-1064 ◽  
Author(s):  
Agylych Atdayev ◽  
Alexander L Danilyuk ◽  
Serghej L Prischepa
Keyword(s):  
Carbon Nanotubes ◽  
Electromagnetic Radiation ◽  
Frequency Dependence ◽  
Shell Morphology ◽  
Magnetic Nanocomposite ◽  
Core Shell ◽  
Ferromagnetic Nanoparticles ◽  
Frequency Range ◽  
Reflection And Transmission

The interaction of electromagnetic radiation with a magnetic nanocomposite based on carbon nanotubes (CNT) is considered within the model of distributed random nanoparticles with a core–shell morphology. The approach is based on a system composed of a CNT conducting resistive matrix, ferromagnetic inductive nanoparticles and the capacitive interface between the CNT matrix and the nanoparticles, which form resonance resistive–inductive–capacitive circuits. It is shown that the influence of the resonant circuits leads to the emergence of specific resonances, namely peaks and valleys in the frequency dependence of the permeability of the nanocomposite, and in the frequency dependence of the reflection and transmission of electromagnetic radiation.

scholarly journals Electromagnetic radiation shielding composite coatings based on powdered alumina and ironoxide

Doklady BGUIR ◽  
2021 ◽  
Vol 19 (3) ◽  
pp. 104-109
Author(s):  
D. I. Penialosa Ovalies ◽  
O. V. Boiprav ◽  
M. V. Tumilovich ◽  
L. M. Lynkou
Keyword(s):  
Iron Oxide ◽  
Electromagnetic Radiation ◽  
Electromagnetic Compatibility ◽  
Composite Coatings ◽  
Radiation Shielding ◽  
Frequency Range ◽  
Reflection And Transmission ◽  
Powdered Iron ◽  
Transmission Coefficients ◽  
Experimental Substantiation

The  article  presents  the  results  of  experimental  substantiation  of  the  method  for  improving the shielding  properties  of  composite  coatings  based  on  powdered  alumina  (electrocorundum,  alum  earth), which  consists  in  modifying  the  composition  of  such  coatings  by adding  to  it  powdered  iron  oxide. This experimental substantiation consisted in the development of the technique for obtaining composite coatings based on powdered alumina and iron oxide, the manufacture of the experimental samplesusing the developed technique,  measurements  of  electromagnetic  radiation  reflection and  transmission  coefficients  values in the frequency range 0.7…17.0 GHz of the manufactured samples; implementation of the comparative analysis of the measured values with the similar values typical for the composite coatings filled with powdered alumina oxides, and composite coatings with the fillers such as powdered iron oxide. The obtained results revealed that by  adding  powdered  iron  oxide  to  the  composite  coatings  based  on powdered  alumina  oxides,  it  is  possible to reduce by 1.0…8.0 dB their electromagnetic radiation transmission coefficient values in the frequency range 0.7…17.0 GHz. In addition, we found that the implementation of the proposed method allows one to decrease by  2.0…20.0  dB  the  electromagnetic  radiation  reflection  coefficient  values  in  the  specified  frequency  range of the considered composite coatings, if such are applied to metal substrates. We propose to use the composite coatings, obtained on the base of the substantiated method, in order to ensure the electromagnetic compatibility of radio-electronic equipment.

scholarly journals Electromagnetic Properties of Cold-Cure Silicone Mixtures Containing Multi-Walled Carbon Nanotubes

2020 ◽  
pp. 043-046
Author(s):  
A.G. Tkachev ◽  
◽  
N.R. Memetov ◽  
R.A. Stolyarov ◽  
N.A. Chapaksov ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Physical Properties ◽  
Electromagnetic Radiation ◽  
Nanocomposite Materials ◽  
Electromagnetic Properties ◽  
Frequency Range ◽  
Concentration Dependences ◽  
Multi Walled Carbon Nanotubes ◽  
Properties Of Materials ◽  
Walled Carbon Nanotubes

Nanocomposite materials based on a cold-cure silicone mixture containing multi-walled carbon nanotubes were obtained. The concentration dependences of the radio-physical properties of materials were investigated. An increase in the efficiency of shielding electromagnetic radiation in the radio frequency range of wavelengths with increasing concentrations of multi-walled carbon nanotubes up to 10 wt. % was verified.

The synthesis and excellent electromagnetic radiation absorption properties of core/shell-structured Co/carbon nanotube–graphene nanocomposites

RSC Advances ◽  
2016 ◽  
Vol 6 (14) ◽  
pp. 11382-11387 ◽  
Author(s):  
Xiaosi Qi ◽  
Qi Hu ◽  
Jianle Xu ◽  
Ren Xie ◽  
Yang Jiang ◽  
...  
Keyword(s):  
Carbon Nanotube ◽  
Electromagnetic Radiation ◽  
Reflection Loss ◽  
Radiation Absorption ◽  
Core Shell ◽  
Frequency Range ◽  
Absorption Properties ◽  
Graphene Nanocomposites ◽  
Microwave Absorbing

We report the synthesis of Co/carbon nanotube–graphene which has attractive microwave absorbing abilities. The optimal reflection loss can reach −65.6 dB with a thickness of 2.19 mm, and RL values below −20 dB for almost the whole frequency range.

scholarly journals Mechanical and electromagnetic pro perties of shields on the base of needle-punched material with conductive and dielectric coatings

2019 ◽  
Vol 64 (1) ◽  
pp. 44-50 ◽  
Author(s):  
H. D. A. Abdulhadi ◽  
A. S. Belousova ◽  
A. M. Prudnik ◽  
L. M. Lynkou
Keyword(s):  
Reflection Coefficient ◽  
Electromagnetic Radiation ◽  
Surface Resistance ◽  
Electromagnetic Compatibility ◽  
Short Circuit ◽  
Frequency Range ◽  
Reflection And Transmission ◽  
Transmission Coefficients ◽  
Dielectric Coatings ◽  
Radiation Shields

The results of the development of electromagnetic radiation shields with flexibility and minor weight and size parameters are presented. Needle-punched material was chosen as the basis for the shields of electromagnetic radiation, which was coated with conductive or dielectric coatings. It has been proved that when applied to a needle-punched material of thin (up to 5 mm) conductive or dielectric coatings, the ultimate strength increases to 5–10 kgf/mm2 and the surface resistance decreases to 0.05 MOhm/sq, while the weight and size parameters of the shields do not change significantly. It was shown that the frequency dependencies of the reflection and transmission coefficients correlate for coatings of various types. A sample of an electromagnetic radiation shields based on a needle-punched coated material consisting of powdered shungite has a reflection coefficient measured in the short circuit mode is about –22.8 dB in the 2–4 GHz frequency range, which allows to use this material to ensure electromagnetic compatibility, information security and personnel protection from electromagnetic radiation.

scholarly journals ELECTROMAGNETIC RADIATION REFLECTION AND TRANSMISSION CHARACTERISTICS OF TWO-LAYER STRUCTURES BASED ON TRANSITION METAL OXIDES

Doklady BGUIR ◽  
2019 ◽  
pp. 93-100
Author(s):  
O. V. Boiprav ◽  
N. V. Bogush ◽  
L. M. Lynkou
Keyword(s):  
Surface Layer ◽  
Transition Metal ◽  
Metal Oxides ◽  
Electromagnetic Radiation ◽  
Transition Metal Oxides ◽  
Reflection And Transmission Coefficients ◽  
Frequency Range ◽  
Reflection And Transmission ◽  
Transmission Coefficients ◽  
Layer Structures

The aim of the work, the results of which are presented in the framework of the article, was to study the of electromagnetic radiation interaction laws in the frequency range 0.7…17 GHz with two-layer structures, the surface layer of which was made using powdered titanium dioxide, and the inner layer was made using a powder material based on oxide ferric iron. The thickness of the layers of the studied structures varied from 0.3 to 1 cm. To achieve this goal, theobjectives associated with the development of a methodology for the manufacture of multilayer structures based on composite materials containing transition metal oxides, as well as with the measurement of such structures samples electromagnetic radiation reflection and transmission coefficients in the frequency range 0.7...17 GHz. These measurements were carried out using a panoramic meter of reflection and transmission coefficients SNA 0.01–17. Based on the obtained measurement results, it was shown that in the frequency range 0.7…2 GHz, the lowest values of electromagnetic radiation reflection coefficient, reaching –20 dB, are characterized by structures whose surface layer thickness is 1 cm, and in the range 2 ... 17 GHz – structures, thickness the surface layer of which is 0.5 or 1 cm (depending on the thickness of the inner layer). The values of electromagnetic radiation transmission coefficient in the frequency range of 0.7...17 GHz of such structures reach –23 dB. Based on the results of the study, it is proposed to use the considered structures in the process of creating shielded rooms or improving the latter (for example, in cases, when it's necessary to reduce the level of passive interference in rooms shielded with metal materials).

Synthesis and Morphology Control of Carbon Nanotube/Polyaniline Composite for Chemical Sensing

2012 ◽  
Vol 1408 ◽  
Author(s):  
Mengning Ding ◽  
Alexander Star
Keyword(s):  
Carbon Nanotubes ◽  
Chemical Sensing ◽  
Single Walled Carbon Nanotubes ◽  
Shell Morphology ◽  
Core Shell ◽  
Solid State Detector ◽  
Sensor Performance ◽  
Increased Sensitivity ◽  
Walled Carbon Nanotubes ◽  
State Detector

ABSTRACTComposites of single-walled carbon nanotubes (SWNTs) and polyaniline (PAni) were synthesized using different approaches. SWNT/PAni nanocomposite with controlled core/shell morphology was achieved. Our chemical sensing tests showed that such core/shell morphology resulted in superior sensor performance, with an increased sensitivity to acetone vapors, and a reversible detection of hydrazine vapors. The reversible detection of parts-per-billion concentrations of hydrazine offers promise for a portable solid-state detector that has potential application in aerospace.

scholarly journals Enhancing Microwave Absorbing Properties of Nickel-Zinc-Ferrite with Multi-walled Carbon Nanotubes (MWCNT) Loading at Higher Gigahertz Frequency

2021 ◽  
pp. 1-7
Author(s):  
Fadzidah Mohd Idris ◽  
Khamirul Amin Matori
Keyword(s):  
Carbon Nanotubes ◽  
Electromagnetic Radiation ◽  
Electromagnetic Interference ◽  
Zinc Ferrite ◽  
Dielectric Materials ◽  
Electronic Systems ◽  
Frequency Range ◽  
Nickel Zinc ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes

The rapid growth of electronic systems and devices operating within the gigahertz (GHz) frequency range has increased electromagnetic interference. In order to eliminate or reduce the spurious electromagnetic radiation levels more closely in different applications, there is strong research interest in electromagnetic absorber technology. Moreover, there is still a lack of ability to absorb electromagnetic radiation in a broad frequency range using thin thickness. Thus, this study examined the effect of incorporating magnetic and dielectric materials into the polymer matrix for the processing of radar absorbing materials. The experiment evaluated the sample preparation with different weight percentages of multi-walled carbon nanotubes (MWCNT) mixed with Ni0.5Zn0.5Fe2O4 (Nickel-Zinc-Ferrite) loaded into epoxy (P) as a matrix. The prepared samples were analysed by examining the reflectivity measurements in the 8 – 18 GHz frequency range and conducting a morphological study using scanning electron microscopy analyses. The correlation of the results showed that different amounts of MWCNT influenced the performance of the microwave absorber. As the amount of MWCNTs increased, the reflection loss (RL) peak shifted towards a lower frequency range and the trend was similar for all thicknesses. The highest RL was achieved when the content of MWCNTs was 2 wt% with a thickness of 2 mm with an RL of – 14 dB at 16 GHz. The 2.5 GHz bandwidth corresponded to the RL below -10 dB (90% absorption) in the range of 14.5 – 17 GHz. This study showed that the proposed experimental route provided flexible absorbers with suitable absorption values by mixing only 2 wt% of MWCNTs.

scholarly journals EXTENSION OF THE FREQUENCY-RANGE OF INTERFEROMETERS FOR THE "MAGNETIC" COMPONENTS OF GRAVITATIONAL WAVES?

2007 ◽  
Vol 22 (13) ◽  
pp. 2361-2381 ◽  
Author(s):  
CHRISTIAN CORDA
Keyword(s):  
Data Analysis ◽  
Frequency Dependence ◽  
Gravitational Waves ◽  
Response Functions ◽  
Frequency Range ◽  
Total Response ◽  
High Frequencies ◽  
Magnetic Components ◽  
Linear Dimensions ◽  
Dominant Part

Recently, with an enlightening treatment, Baskaran and Grishchuk have shown the presence and importance of the so-called "magnetic" components of gravitational waves (GW's), which have to be taken into account in the context of the total response functions of interferometers for GW's propagating from arbitrary directions. In this paper the analysis of the response functions for the magnetic components is generalized in its full frequency dependence, while in the work of Baskaran and Grishchuk the response functions were computed only in the approximation of wavelength much larger than the linear dimensions of the interferometer. It is also shown that the response functions to the magnetic components grow at high frequencies, differently from the values of the response functions to the well-known ordinary components that decrease at high frequencies. Thus the magnetic components could in principle become the dominant part of the signal at high frequencies. This is important for a potential detection of the signal at high frequencies and confirms that the magnetic contributions must be taken into account in the data analysis. More, the fact that the response functions of the magnetic components grow at high frequencies shows that, in principle, the frequency-range of Earth-based interferometers could extend to frequencies over 10000 Hz.

Sign in / Sign up

Export Citation Format

Share Document