Propagation of acoustoelectric waves in a planar layer made of piezoelectrics of hexagonal syngony

1987 ◽  
Vol 23 (7) ◽  
pp. 611-615 ◽  
Author(s):  
I. A. Loza ◽  
K. V. Medvedev ◽  
N. A. Shul'ga
Keyword(s):  
Planar Layer ◽  
Hexagonal Syngony

Transparent Planar Layer Copper Heaters for Wearable Electronics

2021 ◽  
pp. 149895
Author(s):  
Jiyun Choi ◽  
Myunghwan Byun ◽  
Dooho Choi
Keyword(s):  
Wearable Electronics ◽  
Planar Layer

Research of electromagnetic characteristics of planar chiral metastructures based on composite helices components taking into account the heterogeneous Bruggeman model

2020 ◽  
Vol 23 (3) ◽  
pp. 44-55
Author(s):  
Mikhail V. Aralkin ◽  
Andrei N. Dement’ev ◽  
Oleg V. Osipov
Keyword(s):  
Mathematical Model ◽  
Electromagnetic Wave ◽  
Plane Electromagnetic Wave ◽  
Planar Layer ◽  
Chiral Structure ◽  
Linear Algebraic Equations ◽  
Bruggeman Model ◽  
Resonance Frequencies ◽  
Frequency Selective ◽  
Chiral Metamaterial

In this work a mathematical model of a chiral metamaterial is constructed which based on composite fine-wire helices components, which takes into account the properties of chirality, heterogeneity and dispersion. When constructing the model the chiral metamaterial was considered as a heterogeneous system and described by the Bruggeman model. Inthis work, analytical relationships were obtained for calculating the resonance frequencies of composite helices components. Thedispersion properties of the metamaterial were described using the well-known Condon model. As an example of using the constructed mathematical model, we solved the problem of the reflection (transmission) of a plane electromagnetic wave of linear polarization from a planar layer of the chiral structure under study based on composite helices microelements. A system of linear algebraic equations was obtained to determine the reflection and transmission coefficients of the main and cross-polarized field components. As a result of the numerical simulation, the frequency-selective properties of the metastructure were discovered and the frequencies at which the electromagnetic wave is captured by the planar layer of the metastructure were revealed. A similar effect can be used to creation of frequency selective concentrators (hubs) of microwave energy.

Nickel Electrodeposition over Powder Compact for Irradiation Target

2012 ◽  
Vol 727-728 ◽  
pp. 14-19
Author(s):  
Adonis M. Saliba-Silva ◽  
R.H.L. Garcia ◽  
I.C. Martins ◽  
E.F. Urano de Carvalho ◽  
M. Durazzo
Keyword(s):  
Electrical Resistance ◽  
Powder Compact ◽  
Nuclear Reactors ◽  
Nickel Layer ◽  
Planar Layer ◽  
Current Frequency ◽  
Physical Strength ◽  
Nickel Electrodeposition ◽  
Watts Bath ◽  
Enriched Uranium

rradiation targets with 20% of 235U (Low Enriched Uranium - LEU) have been studied to replace HEU (Highly Enriched Uranium) targets in future nuclear reactors. These are used to produce the pair of radionuclides 99Mo / 99mTc, used for diagnostics in nuclear medicine. This work aims to develop an alternative route to produce LEU targets. It consists in hydrogenating and powdering metallic uranium and compacting the produced powder, followed by sealing it with nickel by electrodeposition. The deposited nickel should suppress the release of fission gases, and avoid a reactive contact of uranium with aluminum from the enclosure. In order to obtain the best conditions for deposition over uranium, in this work iron powder was compacted into small discs, with a diameter of 22mm and weight of 14g, simulating an equivalent volume of 10g of LEU uranium powder. As well, aluminum discs were used to ensure adhesion and uniformity of the nickel layer. Pulsed nickel electrodeposition was carried out over the compacts, employing current frequency of 900Hz, -0.84A/cm2 of peak current and duty cycle of 0.5 in Watts Bath. The electrical resistance of pulse Ni-plated layer was checked by experiments with impedance spectroscopy in plated samples using aluminum substrate, held in KCl (pH=6), giving EIS results after resting the discs in solution for 0h, 4h and 24h. The physical strength was evaluated qualitatively by treating the Ni covered compact at 600°C, developing a bump deformation on the original planar layer, up to the point to open the Ni-layer for gas relief. These results suggest an adequate mechanical strength of the Ni-layer for using under neutronic irradiation, sealing the radioactive gases, mainly 140Xe, produced during fission of 235U.

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