• Progress in Superconductivity and Cryogenics
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• v.15 no.1
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• pp.51-54
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• 2013

This paper deals with harmonic components of the voltage on high temperature superconducting wire carrying an alternating current. HTS wire is used to manufacture superconducting power applications carrying an alternating current. Typically, international standard, IEC 61788-3 is used for critical current measurement. Thus, it is not ideal that critical current criteria in dc are adapted to superconducting power devices to decide the operating current of the devices. In this paper, we confirmed odd harmonic voltage on HTS wires carrying an AC. The ratio between harmonic components and fundamental component can be significant clues to decide the critical current criteria for HTS wire and its power applications in AC circumstance.

• Proceedings of the KIEE Conference
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• 1997.07d
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• pp.1399-1401
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• 1997

The stability of superconducting wires was studied by considering temperature and magnetic field. We measured critical current density of $Nb_3Sn$ tape at 4.2 K, 12 K, 13 K and 14 K in various field. The critical current density at 4.2 K, 6 T is 16.5 times higher than at 12 K, 6 T. We expressed the critical current density as a function of temperature and magnetic field, expanding on work by Hampshire, et al.

• Korean journal of food and cookery science
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• v.2 no.2
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• pp.76-83
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• 1986

Time and temperature, pH and Aw, and microbiological evaluation were made to identify critical control points during various phases in product flow of chicken soup preparation in a university foodservice establishment. The results are summarised as follows: 1) Time and temperature data indicated that the phases of cooling after cooking, post-preparation, and holding ingredients at room temperature before assembly were critical. 2) pH and Aw values were in favorable for microbial growth. 3) Microbiological data indicated that the phases of basic ingredients. post-preparation and holding ingredients before assembly were critical. 4) Critical control points identified were; basic ingredients, cooling after cooking, post-preparation, holding before assembly and service, and assembly and service. 5) Several guidelines were suggested for the effective qualitly control program.

• Journal of ILASS-Korea
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• v.26 no.4
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• pp.171-181
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• 2021

This study presents a prediction methodology of thermodynamic properties by using RK-PR Equation of State in a wide range of temperature and pressure conditions including both sub-critical and super-critical regions, in order to obtain thermophysical properties for hydrocarbon aviation fuels and their products resulting from endothermic reactions. The density and the constant pressure specific heat are predicted in the temperature range from 300 to 1000 K and the pressure from 0.1 to 5.0 MPa, which includes all of the liquid and gas phases and the super-critical region of three representative hydrocarbon fuels, and then compared with those data obtained from the NIST database. Results show that the averaged relative deviations of both predicted density and constant pressure specific heat are below 5% in the specified temperature and pressure conditions, and the major sources of the errors are observed near the saturation line and the critical point of each fuel.

• Structural Engineering and Mechanics
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• v.87 no.1
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• pp.29-46
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• 2023

Critical thermal buckling of functionally graded porous (FGP) sandwich plates under various types of thermal loading is considered. It is assumed that the mechanical and thermal nonhomogeneous properties of FGP sandwich plate vary smoothly by distribution of power law across the thickness of sandwich plate. In this paper, porosity defects are modeled as stiffness reduction criteria and included in the rule of mixture. The thermal environments are considered as uniform, linear and nonlinear temperature rises. The critical buckling temperature response of FGM sandwich plates has been analyzed under various boundary conditions. By comparing several numerical examples with the reference solutions, the results indicate that the present analysis has good accuracy and rapid convergence. Further, the effects of various parameters like distribution shape of porosity, sandwich combinations, aspect ratio, thickness ratio, boundary conditions on critical buckling temperature of FGP sandwich plate have been studied in this paper.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.4
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• pp.753-758
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• 2011

Magnetic field and Electric field of High Temperature Superconducting magnet are very important to analysis of superconducting magnet. The maximum perpendicular magnetic field was applied to the outermost pancake windings. The critical current of all the magnet windings is limited by the critical current of the outermost pancake windings. The E-J relation was used to determine the critical current, and an evolution s trategy was adopted for the optimization of gap length between each pancake windins. The results of calculations show that the critical current and the central magnetic field and uniformity increased by 82.6% and 31.6% and 50.8%, respectively, for a magnet consisting of ten pancake windings. This paper did an analysis the cause of increase the critical current and central magnetic field and uniformity in no gap and optimal gap model.

• 한국초전도학회:학술대회논문집
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• v.10
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• pp.8-8
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• 2000

Recently the study of the pseudo-gap in high temperature superconductivity become critical issue because it contains key information of the pair formation of the high temperature superconductivity. Specially angle resolved photoemission study shows the various information of the gap formation. In this talk, I will review the recent theories as will as experiments on the pseudo-gap in high temperature superconductors. Specially I will introduce the possible observation of the Andreeve reflection in the underdopped high temperature superconductors.

• Wind and Structures
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• v.25 no.4
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• pp.381-395
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• 2017

Nonlinear vibration and instability of cylindrical shell conveying fluid-nanoparticles mixture flow are studied in this article. The surrounding elastic medium is modeled by Pasternak foundation. Mixture rule is used for obtaining the effective viscosity and density of the fluid-nanoparticles mixture flow. The material properties of the elastic medium and cylindrical shell are assumed temperature-dependent. Employing first order shear deformation theory (FSDT), the motion equations are derived using energy method and Hamilton's principal. Differential quadrature method (DQM) is used for obtaining the frequency and critical fluid velocity. The effects of different parameters such as volume percent of nanoparticles, boundary conditions, geometrical parameters of cylindrical shell, temperature change, elastic foundation and fluid velocity are shown on the frequency and critical fluid velocity of the structure. Results show that with increasing volume percent of nanoparticles in the fluid, the frequency and critical fluid velocity will be increases.

• Progress in Superconductivity
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• v.7 no.1
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• pp.22-27
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• 2005

We have studied the standardization of critical temperature measurements by using an ac susceptometer. Wire forms of NbTi, $Nb_{3}Sn$, and Bi-2223 superconductors were prepared to measure the temperature dependences of the magnetization. In order to study the optimum ac magnetic field and frequency, various amplitudes from 2 Oe to 10 Oe with frequencies from 11.3 Hz to 1033 Hz were applied to three specimens. Analytical comparison of the magnetic curves with the resistive curves was accomplished to investigate validity of using the new method.

• Progress in Superconductivity
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• v.12 no.1
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• pp.36-40
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• 2010

We have studied the anisotropy of the London penetration depth of carbon doped $MgB_2$ single crystals, which was obtained from reversible magnetization measurements with the magnetic field both parallel and perpendicular to the c-axis. Similar to the pure $MgB_2$, the anisotropy of the upper critical field ${\gamma}_H$ decrease with temperature while the anisotropy of the London penetration depth ${\gamma}_{\lambda}$ slowly increases with temperature. However, the temperature dependence of ${\gamma}_H$ is drastically reduced and the value of ${\gamma}_{\lambda}$ becomes nearly ~1 as C is introduced. These results indicate that C substitution increases impurity scattering mainly in the $\sigma$ bands. The temperature dependence of the anisotropies agree well with the theoretical predictions with impurity scattering.