scholarly journals TECHNOLOGY OF MANUFACTURE OF RADIO ABSORPTION CERAMICS

Author(s):  
George Lisachuk ◽  
Ruslan Kryvobok ◽  
Artem Zakharov ◽  
Valentyna Voloshchuk ◽  
Mykyta Maistat ◽  
...  

The object of the work is the technology of manufacturing radio-absorbing ceramics on the basis of facing tiles with the addition of silicon carbide. The method of hydrostatic weighing in water was used to determine the physical properties. X-ray phase analysis and spectral characteristics - transmission and reflection coefficients, in the frequency range 25.8 – 37.5 GHz were also determined. Tiles consist of two layers. First, separately obtain a press powder for the I and II layer of raw materials in a given amount, which were weighed, moistened, ground in a ball mill; the slip was dried in an oven, then ground and passed through a suitable sieve. The moistened press powder for the first layer was weighed and poured into a mold for pressing, after which the moistened press powder for the second layer was weighed and poured into the mold for pressing. The resulting raw material was dried. The semi-finished product was covered with watering and placed in an oven. The finished semi-finished product was fired in a silite furnace. The two-layer tile with an irrigated covering made on the developed technology was characterized by the following characteristics: water absorption – 9,8 %, imaginary density – 1,90 g/cm3. The developed ceramics, according to the classification, can be referred to the class of radio-absorbing ceramics.

2018 ◽  
Vol 74 (3) ◽  
pp. 204-215 ◽  
Author(s):  
Minas K. Balyan

For the asymmetrical Laue case the X-ray plane-wave transmission and reflection coefficients and rocking curves are analysed as a function of the deviation angles from the exact Bragg orientation in the diffraction plane and in the direction perpendicular to the diffraction plane. New peculiarities of the rocking curves are obtained. The peculiarities of both the effective absorption coefficient and rocking curves in thick crystals are also investigated.


Materials ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3499
Author(s):  
Anatoly B. Rinkevich ◽  
Dmitry V. Perov ◽  
Yuriy I. Ryabkov

The microwave properties of a composite material containing flakes of finemet-type nanocrystalline alloy placed in the epoxy matrix have been investigated. Two compositions have been studied: with 15% and 30% flakes. Frequency dependences of transmission and reflection coefficients are measured in the frequency range from 12 to 38 GHz. The dielectric permittivity and magnetic permeability are obtained, and the microwave losses are calculated. The dependences of transmission and reflection coefficients have been drawn as functions of wave frequency and thickness of the composite material, taking into account the frequency dependences of permittivity and permeability. The regions of maximal and minimal microwave absorption have been defined. The influence of wave interference on the frequency dependence of microwave absorption is studied.


Author(s):  
O. Langueur ◽  
M. Merad ◽  
A. Rassoul

In this paper, we study the Duffin–Kemmer–Petiau (DKP) equation in the presence of a smooth barrier in dimensions space–time (1+1) dimensions. The eigenfunctions are determined in terms of the confluent hypergeometric function [Formula: see text]. The transmission and reflection coefficients are calculated, special cases as a rectangular barrier and step potential are analyzed. A numerical study is presented for the transmission and reflection coefficients graphs for some values of the parameters [Formula: see text] are plotted.


Author(s):  
Hironori Tohmyoh

Abstract This paper presents the materials evaluation and environmental monitoring techniques utilizing the acoustic resonance, which have been developed by the authors. When the ultrasound passes through thin layer, the transmission and reflection coefficients take their maximum and the minimum values at the resonant frequency. We call this acoustic resonance. The acoustic properties of a polymer film, e.g., the acoustic impedance, ultrasonic velocity, and density, can be determined by observing the acoustic resonance, which occurs at the water/film/reflection plate interface. Acoustic resonance occurs at the reflection plate/film/outer environment interface sensitively changes depending on the outer environment. With use of this, the temperature of the water as an outer environment is tried to be monitored.


2019 ◽  
Vol 34 (16) ◽  
pp. 1950087 ◽  
Author(s):  
Luis Puente ◽  
Carlos Cocha ◽  
Clara Rojas

We present a new potential barrier that presents the phenomenon of superradiance when the reflection coefficient [Formula: see text] is greater than one. We calculated the transmission and reflection coefficients for three different regions. The results are compared with those obtained for the hyperbolic tangent potential barrier and the step potential barrier. We also present the solution of the Klein–Gordon equation with the Lambert-[Formula: see text] potential barrier in terms of the Heun Confluent functions.


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