Browsing by Author "CHEN, RC"

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BOLOMETRIC RESPONSE OF HIGH-T-C SUPERCONDUCTING DETECTORS TO OPTICAL PULSES AND CONTINUOUS WAVES
(1995-05-01)
CHEN, RC
;
WU, JP
;
CHU, HS
;
交大名義發表
;
機械工程學系
This work presents a thermal analysis on predicting the temperature increase and the voltage response of high-T-c superconducting bolometers. Two heat transfer models, that is, the surface heating model and the heat generation model considering the skin depth, are introduced and compared. The surface heating model is found to be valid only for situations where the skin depth is much smaller than the film thickness. To consider the thermal boundary resistance between film and substrate, a radiation-boundary-condition model based on acoustic mismatch model (AMM) and an interfacial-layer model (ILM) are employed. The thermal boundary resistance significantly influences the voltage response. Additionally, several common substrates are examined. SrTiO3 (100) or LaAlO3 (100) is a better substrate for high-T-c superconducting bolometers. One interesting finding was that when compared with experimental data, all the theoretical values from the present study as well as the other previously theoretical treatment overestimate the voltage response near the transition temperature.
STUDY ON THE INTRINSIC THERMAL-STABILITY OF ANISOTROPIC THIN-FILM SUPERCONDUCTORS WITH A LINE HEAT-SOURCE
(1991-08-01)
CHEN, RC
;
CHU, HS
;
交大名義發表
;
機械工程學系
;
National Chiao Tung University
This paper presents an analytical method to investigate the intrinsic thermal stability of anisotropic thin film superconductors. A three-dimensional analysis is introduced to consider an instantaneous release of energy in the form of a finite length line source. Through the transformation of coordiantes, an isotropic form of heat conduction equation is obtained. To solve this initial and boundary value problem, the method of separation of variables is employed, which gives an exact solution. The results of limiting cases of this study are compared with those of two previous investigations. Results from this study also show that the anisotropy of highly orientated films of superconductors has a great impact on the thermal stability. The stability parameter also depends on the location of the line source, the length of the line source, the magnitude of disturbance energy, the Biot number and the aspect ratio in the plane of thin film and normal to it.
STUDY ON THE INTRINSIC THERMAL-STABILITY OF THIN-FILM SUPERCONDUCTORS DUE TO A POINT HEAT-SOURCE
(1992-09-01)
CHU, HS
;
CHEN, RC
;
交大名義發表
;
機械工程學系
;
National Chiao Tung University
Intrinsic thermal stability denotes a situation where a superconductor can carry the operating current without Joule heating at all times after the occurrence of a localized release of thermal disturbance. The present work deals with the intrinsic thermal stability of an anisotropic thin-film superconductor under a localized release of thermal energy. A three-dimensional analysis is introduced to consider an instantaneous release of energy in the form of a point source at different locations. Through the transformation of coordinate, an exact solution is obtained by the method of separation of variables. Results from this study indicate that the thermal stability parameter of highly oriented films of superconductors is strongly under the influence of anisotropy. The stability parameter also depends on the location of point source, the amount of disturbance energy, the Biot number, and the aspect ratio in the plane of thin film and normal to it.
THERMAL-ANALYSIS OF HIGH-T(C) SUPERCONDUCTING BOLOMETERS
(1993-12-01)
WU, JP
;
CHEN, RC
;
CHU, HS
;
交大名義發表
;
機械工程學系
In this work we have presented a 2D analysis on predicting the temperature increase and the voltage response of high-T(c) superconducting bolometers. A heat generation model is used to consider absorption of irradiation of energy by film. The type of laser beam is continuous waves (CW). To consider the thermal boundary resistance, a radiation-boundary-condition model based on acoustic mismatch model (AMM) is employed. The effects of the incident energy and radius of laser beam, as well as the thermal conductivity ratio in x and y directions for thin-film superconductors on the voltage response are investigated. The results of our work are also compared with previously experimental and 1D theoretical analyses for various initial temperatures.