scholarly journals Justification of binder material selection for carbon particles incorporation into fibrous electromagnetic radiation absorber

Doklady BGUIR ◽  
2020 ◽  
Vol 18 (6) ◽  
pp. 88-93 ◽  
Author(s):  
E. S. Belousova ◽  
B. I. Dumchev ◽  
M. S.Kh. Al-Mahdawi
Keyword(s):  
Carbon Black ◽  
Electromagnetic Radiation ◽  
Active Substance ◽  
Fibrous Material ◽  
Mechanical Deformation ◽  
Surface Active Substance ◽  
Frequency Range ◽  
Carbon Particles ◽  
Surface Active ◽  
Binder Material

The paper presents justification of a binder material for incorporating carbon particles into the interfiber space of electromagnetic radiation absorber. A method for carbon particles incorporation into a fibrous material has been developed. It is based on applying a carbon-containing nanocomposite to the fibrous material’s surface. Previously, the research of carbon particles incorporation into a synthetic material by using an aqueous solution were carried out, which ensured a uniform distribution of carbon particles in the material structure. However, the properties of the material have changed significantly upon mechanical deformation. Therefore, the carbon particles incorporation process was investigated using various nanocomposites obtained on the basis of mixtures of vinyl acetate polymer, or epoxy polymer, or surface-active substance with carbon black. Based on the results of electron microscopic analysis and the reflection and transmission coefficients frequency dependences in the frequency range 0.7–17 GHz, the efficiency of using a nanocomposite based on a mixture of surface-active substance and carbon black to create electromagnetic radiation absorbers was justified. Such electromagnetic radiation absorbers have the transmission coefficient value about –18 dB and reflection coefficient value about –12 dB in the frequency range 7–13 GHz. Carbon-containing electromagnetic radiation absorbers based on fibrous material have thickness less than 3 mm, properties of flexibility and resistance to mechanical deformation. It can be used in various fields, in particular for hiding objects from radio frequency reconnaissance or protecting equipment from external interference.

scholarly journals INFLUENCE OF SPEED, TIME OF HOMOGENIZATION, TYPE OF SURFACE ACTIVE SUBSTANCE ON THE SIZE OF PENTOXYPHILLINE NANOPARTICLES BASED ON POLY-DL-LAKTIDE-CO-GLICOLIDE

2017 ◽  
Vol 5 (2) ◽  
pp. 177-194 ◽  
Author(s):  
T. V. Timchenko ◽  
A. V. Blinov ◽  
A. V. Serov ◽  
L. I. Shcherbakova ◽  
V. A. Kompantsev ◽  
...  
Keyword(s):  
Active Substance ◽  
Surface Active Substance ◽  
Surface Active

scholarly journals THE ROLE OF WATER IN PROTOPLASMIC PERMEABILITY AND IN ANTAGONISM

1956 ◽  
Vol 39 (6) ◽  
pp. 963-976 ◽  
Author(s):  
W. J. V. Osterhout
Keyword(s):  
Surface Layer ◽  
Water Content ◽  
Active Substance ◽  
External Medium ◽  
Surface Active Substance ◽  
Potassium Ions ◽  
Protoplasmic Surface ◽  
Outer Protoplasmic Surface ◽  
Aqueous Surface ◽  
Surface Active

The behavior of the cell depends to a large extent on the permeability of the outer non-aqueous surface layer of the protoplasm. This layer is immiscible with water but may be quite permeable to it. It seems possible that a reversible increase or decrease in permeability may be due to a corresponding increase or decrease in the water content of the non-aqueous surface layer. Irreversible increase in permeability need not be due primarily to increase in the water content of the surface layer but may be caused chiefly by changes in the protoplasm on which the surface layer rests. It may include desiccation, precipitation, and other alterations. An artificial cell is described in which the outer protoplasmic surface layer is represented by a layer of guaiacol on one side of which is a solution of KOH + KCl representing the external medium and on the other side is a solution of CO2 representing the protoplasm. The K+ unites with guaiacol and diffuses across to the artificial protoplasm where its concentration becomes higher than in the external solution. The guaiacol molecule thus acts as a carrier molecule which transports K+ from the external medium across the protoplasmic surface. The outer part of the protoplasm may contain relatively few potassium ions so that the outwardly directed potential at the outer protoplasmic surface may be small but the inner part of the protoplasm may contain more potassium ions. This may happen when potassium enters in combination with carrier molecules which do not completely dissociate until they reach the vacuole. Injury and recovery from injury may be studied by measuring the movements of water into and out of the cell. Metabolism by producing CO2 and other acids may lower the pH and cause local shrinkage of the protoplasm which may lead to protoplasmic motion. Antagonism between Na+ and Ca++ appears to be due to the fact that in solutions of NaCl the surface layer takes up an excessive amount of water and this may be prevented by the addition of suitable amounts of CaCl2. In Nitella the outer non-aqueous surface layer may be rendered irreversibly permeable by sharply bending the cell without permanent damage to the inner non-aqueous surface layer surrounding the vacuole. The formation of contractile vacuoles may be imitated in non-living systems. An extract of the sperm of the marine worm Nereis which contains a highly surface-active substance can cause the egg to divide. It seems possible that this substance may affect the surface layer of the egg and cause it to take up water. A surface-active substance has been found in all the seminal fluids examined including those of trout, rooster, bull, and man. Duponol which is highly surface-active causes the protoplasm of Spirogyra to take up water and finally dissolve but it can be restored to the gel state by treatment with Lugol solution (KI + I). The transition from gel to sol and back again can be repeated many times in succession. The behavior of water in the surface layer of the protoplasm presents important problems which deserve careful examination.

Electromagnetic Wave Absorption Properties of Glass Fiber Reinforced Cement Filled with Carbon Black

2014 ◽  
Vol 912-914 ◽  
pp. 127-130 ◽  
Author(s):  
Yao Li Wei ◽  
Yue Fang Zhang ◽  
Wang Jun Hao
Keyword(s):  
Carbon Black ◽  
Electromagnetic Radiation ◽  
Glass Fiber ◽  
High Frequency ◽  
Frequency Range ◽  
Absorption Properties ◽  
Testing Method ◽  
Glass Fiber Reinforced ◽  
New Material ◽  
Reinforced Cement

In order to deal with the more and more serious problem of electromagnetic radiation pollution, cement-based composites were prepared by introducing glass fiber into cement as through wave reagent and carbon black as absorbing reagent . Arched testing method were used to test the reflection losses in the frequency range of 2~18 GHz. The results showed that the absorption properties were improved in high frequency compared with the pure cement. The filling ratio of carbon black and glass fiber as well as the thickness of samples had influence on the absorption properties. The lowest reflection loss of-11.2 dB was obtained at 18 GHz of 9wt.% glass fiber and 5wt.% carbon black filled cement with thickness of 10mm. The new material can be used for building indoor electromagnetic radiation protection.

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