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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
> Journal Vol & Issue
Progress in Superconductivity and Cryogenics
Journal Basic Information
Journal DOI :
The Korea Institute of Applied Superconductivity and Cryogenics
Editor in Chief :
Volume & Issues
Volume 2, Issue 2 - Nov 2000
Volume 2, Issue 1 - May 2000
Selecting the target year
Effects of F-doping on perparation and superconducting characteristics of ag-sheathed Tl-1223 tapes
Progress in Superconductivity and Cryogenics, volume 2, issue 1, 2000, Pages 1~6
The effects of partial substitution of fluorine on physical properties were studied in Ag-sheathes tapes of
nominal compositions. The tapes were prepared using the powder-in-tube method incorporating an in-situ reaction method.
was used as a source of F. It was found that F-doping in Tl-1223 system resulted in a decrease in formation temperatire of Tl-1223 phase. and thus significantly deteriorated their superconducting properties. Such disadvantages seem to originate by the fromation of non-beneficial phases such as SrF2 in the early stage of the powder preparation process.
Experimental of the Rotaing Cryogenic System
Progress in Superconductivity and Cryogenics, volume 2, issue 1, 2000, Pages 7~13
A rotating cryogenic system was designed similar to the cooling system for the rotor of a superconducting generator. The experimental rotor has an inner vessel which simulates the winding space of an actual superconducting rotor, and a torque tube of comparable design. This paper describes the evaluation of the total heat leak into the inner vessel that leads to the study of the heat transfer characteristic of the rotating cryogenic system. To examine the insulation performance of the experimental rotor. temperature was measured at each part of the system at various rotaing speeds from 0 rpm to 600 rpm. Total heat leak into the inner vessel was calculated by measuring the boil-off rate of liquid helium. Conduction heat leak to the inner vessel was obtained by the vent tube, and radiation heat leak was calculated by subtracting the conduction heat lent from the total heat leak. There seemed to be no rotaional dependency of total heat leak at least up 600 rpm.
Design, Manufacture and Characteristic Experiment of a Superconducting power Supply with Superconducting Excitation Coil
Progress in Superconductivity and Cryogenics, volume 2, issue 1, 2000, Pages 14~18
This paper describes a series of experiments to investigate the operational characteristics of a superconducting power supply with superconducting excitation coil. In this experiment, the superconducting excitation coil is introduced to control the pole-flex in the air gap of the machine. The operating current of the superconducting powder supply is designed to have the value of 300 [A] for the rotational speed of 600 rpm. Sensors installed on the Nb sheet yield the information on the spatial and temporal behaviors of the magnetic field in spot and on the characteristics of the superconducting power supply.
Stability and Quench Charcteristics of the SC Conductor for a
Progress in Superconductivity and Cryogenics, volume 2, issue 1, 2000, Pages 19~23
We are developing a small-sized superconducting magnetic energy storge (
SMES) magnet with the storage capacity of a few megajoules, which provides electric power with high quality to sensitive electric loads. A kA class superconductor with a high coppe
erconductor ratio was selected as a candidate conductor. The superconductor was tested in two points of view, which are basic and important in development of the
SMES magnet. First, stabilities of the superconductor against localized disturbances such as wire motions were estimated by using a wire heater. Second, the quench current characteristics for different charge rates were also tested. The stability data showed that the short heat pulses made the conductor more unstable. The superconductor had relatively high recovery currents ranging between 40% and 50% of its critical currents. The quench tests indicated that the quench currents of the conductor were independent of current ramp rates up to 3000 A/s and nearly equal to its cuitical current data.ta.
Arc Phenomena and Induced Voltage due to Inductive Energy of Superconducting Coil
Progress in Superconductivity and Cryogenics, volume 2, issue 1, 2000, Pages 24~30
This paper present the characteristics of the internal induced voltage and arc phenomena in liquid helium at the energy transfer from a superconducting magnet to a load resistor. Especially generation mechanism of the oscillated wave from of the coil terminal voltage is analyzed by considering circuit constant of the superconducting magnet, load condition and arc resistance of the mechanical opening switch. The wavefront and peak portion of the voltage are strongly influenced by arc discharge triggered by the switch separation in liquid helium. Abrupt arc extinction leads to voltage oscillation with an enormous peak. It is suggested that the superconducting magnet should be designed to ensure the internal surge when arc is possibly formed by switch opening or coil short circuit between turns or layers. Finally, a suppression method of the oscillating surge is proposed based on the load condition.
The Initial Magnetic Field Decay of the Superconducting Magnet in the Persistent Current Mode
Progress in Superconductivity and Cryogenics, volume 2, issue 1, 2000, Pages 31~34
this paper deals with the initial magnetic field decay for a large scale superconducting magnet e.g. NMR/MRI magnet. The high resolution image can not be obained during the periods of the initial field decay. It is known that all superconducting materials have the property of diamagnetism. This diamagnetism is usually explained with the concept of screening current. We assumed that the existence of the screening currebt. we assumed that the existence of the screening current makes the current distribution in the superconducting wire non-uniform. And the initial magnetic field decay is caused steady current state in the view of its pattern. The initial magnetic field decay is caused by the change of the current distribution between the energizing state and persistent current mode. in this paper the theoretical analysis for the current distributions has been introduced for each state. The experiments have been carried out to verify transport currents in order to veperiments, it small at the higher transport current.
Analysis on Quench Propagation Characteristics of HTS Tape
Lee, Ji Gwang ; Kim, Ji Hun ; Ryu, Gyeong U ; Cha, Gwi Su ; Han, Song Yeop ;
Progress in Superconductivity and Cryogenics, volume 2, issue 1, 2000, Pages 35~35
The main issues for the power application of High Tc superconducting tape are lower AC loss and higher stability conditions. HTS tape has large stability margin by high heat capacity of superconductor itself and high temperature margin. But, it can be damaged by continuous heat generation at quench point, because normal zone propagation velocity by generating heat is very low. Here, we analyze the quench propagation characteristics using finite element method for BSCCO-2223 HTS tape.
Analysis on Quench Propagation Charactreristics of HTS Tape
Progress in Superconductivity and Cryogenics, volume 2, issue 1, 2000, Pages 36~39
The main issues for the power application of high Tc superconducting tape are lower AC loss and higher stability conditions. HTS tape has large stability margin by high heat capacity of superconductor itself and high temperature margin. But, it can be damaged by continuous heat generation at quench point, because normal zone propagation velocity by generating heat is very low. Here, we analyze the quench propagation characteristics using finite element method for BSCCO-2223 HTS tape.
Coouping Losses of the Round HTS Wires with Stacked Filaments and Radial Filaments
Progress in Superconductivity and Cryogenics, volume 2, issue 1, 2000, Pages 40~44
The round HTS wire is easier to handle than the rectangular HTS tape. This paper describes the coupling losses of the round HTS wires by finite element method. Effect of the round HTS wire are considered. Two types of Filaments arrangement, stacked filament and radial filaments, are considered. Calculation results show that coupling losses of the round HTS wire vary only a little with the direction of external magnetic field.
Experimental study on the transfer in pulse tube
Progress in Superconductivity and Cryogenics, volume 2, issue 1, 2000, Pages 45~50
The present study has been conducted to observe the heat transfer under pulsating pressure and oscillating flow. The experimental apparatus was fabricated to measure the gas temperature, the wall temperature. the pressure and the instantaneous heat flux inside the pulse tube. The measured gas temperature and heat flux must be calibarated to compensate their finite time constant in the oscillating flow conditious. The experiment was performed from 1 Hz to 5 Hz. The phase difference between the instantaneous heat flux and the gas-wall temperature difference was clearly observed. The experimental heat fluxes were compared to the theroretical correlations such as Complex Nusselt Number Model(CNNM) and Variable Coefficient Model(CVM). The heat flux predisted by CNNM was always greater than that of VCM. The experiment confirmed the valisity of the VCM for the instantaneous heat flux under the pulsating pressure and oscillating flow in the warm end of the pulse tube.