scholarly journals Direct-current-assisted microwave quenching of YBa2Cu3O7−δ coplanar waveguide to a highly dissipative state

2014 ◽  
Vol 105 (2) ◽  
pp. 022601 ◽  
Author(s):  
N. T. Cherpak ◽  
A. A. Lavrinovich ◽  
A. I. Gubin ◽  
S. A. Vitusevich
Keyword(s):  
Direct Current ◽  
Coplanar Waveguide ◽  
Dissipative State

scholarly journals Сверхпроводящий источник шума для сверхнизких температур

2021 ◽  
Vol 47 (24) ◽  
pp. 13
Author(s):  
Т.М. Ким ◽  
С.В. Шитов
Keyword(s):  
Direct Current ◽  
Shot Noise ◽  
Tunnel Junction ◽  
Normal State ◽  
Coplanar Waveguide ◽  
Heating Power ◽  
Temperature Modulation ◽  
Frequency Range

The device operates at temperatures <300 mK and comprises a hafnium microbridge and a superconducting aluminum tunnel junction both integrated into a common coplanar waveguide. The microbridge is a thermodynamic source and operates as an optical blackbody at frequencies 600–700 GHz. The coplanar terminal is the blackbody output in the 1–2 GHz frequency range. The microbridge temperature can be set in the range of 0.4–9 K and calibrated using the shot noise of the tunnel junction. Activation and temperature modulation of each of the sources can be performed independently using a direct current which transit them from the superconducting to the normal state with characteristic times <0.1 ms and heating power <1 μW.

scholarly journals To the Phenomenological theory of Avalanche-Like Effect in Dc-Biased Microwave Nonlinear HTS Transmission Line

2019 ◽  
Vol 64 (10) ◽  
pp. 962 ◽  
Author(s):  
S. I. Melnyk ◽  
S. S. Melnyk ◽  
A. A. Lavrinovich ◽  
M. T. Cherpak
Keyword(s):  
Transmission Line ◽  
Direct Current ◽  
Phenomenological Model ◽  
Phenomenological Theory ◽  
Mathematical Apparatus ◽  
Proposed Model ◽  
Fold Type ◽  
Microwave Losses ◽  
Dissipative State

A phenomenological model has been proposed to describe the avalanche-like transition of a microwave nonlinear HTSC-based transmission line into a dissipative state. This effect was observed by the authors in a dc-biased transmission line. The proposed model generalizes the well-known phenomenological model for the nonlinear HTSC-based transmission line under the action of a direct current. The character of the dependences obtained for microwave losses allows the jump-like changes in the properties of the nonlinear HTSC-based transmission line to be regarded as a fold-type catastrophe and the methodological and mathematical apparatus of the theory of catastrophes to be used in order to explain the results obtained and predict new ones.

scholarly journals On kinetics of superconducting state destruction in a nonlinear coplanar waveguide based on a high-temperature superconductor film

2021 ◽  
Vol 26 (1) ◽  
pp. 49-57
Author(s):  
O. Lavrinovich ◽  
◽  
N. Cherpak ◽  
Keyword(s):  
High Temperature ◽  
Direct Current ◽  
Superconducting State ◽  
High Temperature Superconductor ◽  
Landau Equation ◽  
Coplanar Waveguide ◽  
Motion Equation ◽  
Superconducting Film ◽  
Order Of Magnitude ◽  
Kinetics Of

Subject and Purpose. The mechanism of destruction of the S-state of a nonlinear high-temperature superconductor as part of a coplanar waveguide has not been properly elucidated as the effect of avalanche-type transition to a highly dissipative state, which was experimentally detected by the authors, takes place. The present work is concerned with the development of an appropriate approach describing kinetics of destruction of the S-state of a nonlinear high-temperature superconductor in a coplanar waveguide with allowances made for an inhomogeneous distribution of the microwave current in the superconducting film strip. Methods and Methodology. Use of I.B. and O.G. Vendiks’ reasoning [2] is made on kinetics of the destruction of the superconducting state of a wide film when a direct current governed by the time-dependent Ginzburg-Landau equation is applied. Keeping unchanged their idea as to the S–N boundary forming in the film strip with the boundary movement to the middle of the strip, the S–N boundary motion equation is obtained for a coplanar waveguide, proceeding in doing this from the motion equation of magnetic flux vortices under certain restrictions specified. Results. The time of S-state destruction has been numerically estimated: 1) for a wide superconducting film of YBa2Cu3O7–d composition, the destruction is by the direct current and 2) for a coplanar waveguide based on the same film, the destruction is by the microwave current. When the superconductivity is small (I / I c ³ 1), the destruction time values in both cases are close to each other within the order of magnitude. Conclusion. It is for the first time that the S-state destruction time in a coplanar waveguide has been expressed in terms of the microwave current distribution in the waveguide. It has been shown that this characteristic linearly depends on the ratio between the critical current and the microwave current amplitude in contrast to a quadratic dependence obtained for a superconducting strip with a direct current.

Inter-Method Reliability of Pulse Volume Related Measures Derived Using Finger-Photoplethysmography

2018 ◽  
Vol 32 (4) ◽  
pp. 182-190 ◽  
Author(s):  
Kenta Matsumura ◽  
Koichi Shimizu ◽  
Peter Rolfe ◽  
Masanori Kakimoto ◽  
Takehiro Yamakoshi
Keyword(s):  
Light Intensity ◽  
Adverse Effects ◽  
Light Source ◽  
Direct Current ◽  
Resting State ◽  
Current Component ◽  
Psychophysiological Measures ◽  
Pulse Volume ◽  
Optical Paths ◽  
Sensor Positions

Abstract. Pulse volume (PV) and its related measures, such as modified normalized pulse volume (mNPV), direct-current component (DC), and pulse rate (PR), derived from the finger-photoplethysmogram (FPPG), are useful psychophysiological measures. Although considerable uncertainties exist in finger-photoplethysmography, little is known about the extent of the adverse effects on the measures. In this study, we therefore examined the inter-method reliability of each index across sensor positions and light intensities, which are major disturbance factors of FPPG. From the tips of the index fingers of 12 participants in a resting state, three simultaneous FPPGs having overlapping optical paths were recorded, with their light intensity being changed in three steps. The analysis revealed that the minimum values of three coefficients of Cronbach’s α for ln PV, ln mNPV, ln DC, and PR across positions were .948, .850, .922, and 1.000, respectively, and that those across intensities were .774, .985, .485, and .998, respectively. These findings suggest that ln mNPV and PR can be used for psychophysiological studies irrespective of minor differences in sensor attachment positions and light source intensity, whereas and ln DC can also be used for such studies but under the condition of light intensity being fixed.

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