TEMPERATURE DEPENDENCE OF JOSEPHSON PLASMA MODES IN Bi2Sr2CaCu2O8+δ NEAR Tc

2000 ◽  
Vol 14 (05) ◽  
pp. 547-554
Author(s):  
KAZUO KADOWAKI ◽  
ITSUHIRO KAKEYA ◽  
TETSU WAKABAYASHI ◽  
RYO NAKAMURA ◽  
SABURO TAKAHASHI
Keyword(s):  
Plasma Frequency ◽  
Fluid Model ◽  
Microwave Frequency ◽  
Tunneling Probability ◽  
Temperature Dependent ◽  
Plasma Energy ◽  
Longitudinal Plasma ◽  
Two Fluid Model ◽  
Two Fluid ◽  
Josephson Plasma

A strong temperature dependent phenomenon of the Josephson plasma resonance mode has been found in high-Tc superconductor Bi 2 Sr 2 CaCu 2 O 8+δ in a microwave frequency region between 9 and 50 GHz. The longitudinal plasma frequency sharply decreases and disappears just below Tc. The extrapolated plasma energy is estimated to be ℏω p (0)=2.59× 10-4 eV . Since the plasma frequency, ω p , is determined by the Anderson-Higgs–Kibble mechanism and it is expected to be temperature independent, this phenomenon can not be accounted for by the conventional underst and ing of the plasma mode in superconductors. Experimental results are discussed in terms of the two fluid model, in which the intrinsic Josephson nature of the coupling restricting the tunneling probability of quasiparticles between layers is considered to be as a dumping mechanism of the quasiparticles in this system.

Transmittance in a dispersive quasiperiodic photonic crystal

2021 ◽  
Vol 35 (04) ◽  
pp. 2150061
Author(s):  
Francis Segovia-Chaves ◽  
Herbert Vinck-Posada ◽  
Edgar A. Gómez
Keyword(s):  
Dielectric Constant ◽  
Photonic Crystal ◽  
High Temperature Superconductor ◽  
Plasma Frequency ◽  
Fluid Model ◽  
Band Gaps ◽  
Transmittance Spectrum ◽  
One Dimensional ◽  
Two Fluid Model ◽  
Two Fluid

In this work, transmittance spectrum for a quasiperiodic one-dimensional photonic crystal, composed of high-temperature superconductor and semiconductor layers arranged within the crystal based on a Dodecanacci sequence, has been calculated using the transfer matrix method and the two-fluid model. The critical temperature of the superconductor depends on the hydrostatic pressure, while the semiconductor’s plasma frequency and dielectric constant were considered to be dependent on both the pressure and temperature applied. We have found that the transmittance spectrum shows the band gaps unfolded and increased in number when the Dodecanacci sequence increased. In addition, this work shows that transmission responses can be tuned to higher frequencies as pressure increases. However, a small red shift of the transmittance spectrum can be observed as temperature increases. Finally, the research observed the maximization of the band gaps by increasing the thickness of the superconductor layers. We hope this work may be considered for application in tunable narrowband filters.

scholarly journals Natural modes of the two-fluid model of two-phase flow

2021 ◽  
Vol 33 (3) ◽  
pp. 033324
Author(s):  
Alejandro Clausse ◽  
Martín López de Bertodano
Keyword(s):  
Two Phase Flow ◽  
Fluid Model ◽  
Phase Flow ◽  
Two Phase ◽  
Natural Modes ◽  
Two Fluid Model ◽  
Two Fluid

Self-consistent hydrodynamic two-fluid model of vortex plasma

2021 ◽  
Vol 33 (3) ◽  
pp. 037116
Author(s):  
Victor L. Mironov
Keyword(s):  
Fluid Model ◽  
Self Consistent ◽  
Two Fluid Model ◽  
Two Fluid

scholarly journals Mathematical study on two-fluid model for flow of K–L fluid in a stenosed artery with porous wall

2021 ◽  
Vol 3 (4) ◽  
Author(s):  
R. Ponalagusamy ◽  
Ramakrishna Manchi
Keyword(s):  
Theoretical Study ◽  
Fluid Model ◽  
Porous Wall ◽  
Governing Equations ◽  
Rate Of Increase ◽  
Special Cases ◽  
Stenosed Artery ◽  
Flow Through ◽  
Two Fluid Model ◽  
Two Fluid

AbstractThe present communication presents a theoretical study of blood flow through a stenotic artery with a porous wall comprising Brinkman and Darcy layers. The governing equations describing the flow subjected to the boundary conditions have been solved analytically under the low Reynolds number and mild stenosis assumptions. Some special cases of the problem are also presented mathematically. The significant effects of the rheology of blood and porous wall of the artery on physiological flow quantities have been investigated. The results reveal that the wall shear stress at the stenotic throat increases dramatically for the thinner porous wall (i.e. smaller values of the Brinkman and Darcy regions) and the rate of increase is found to be 18.46% while it decreases for the thicker porous wall (i.e. higher values of the Brinkman and Darcy regions) and the rate of decrease is found to be 10.21%. Further, the streamline pattern in the stenotic region has been plotted and discussed.

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