• Progress in Superconductivity and Cryogenics
• /
• v.25 no.3
• /
• pp.34-37
• /
• 2023

The practical application of REBCO coated conductor (CC) tapes, vital for energy transmission (e.g., cable application) and high-field magnets (e.g., coil application), necessitates efficient and simple quality assessment procedures. This study introduces a systematic approach to assess the electromechanical properties of REBCO CC tapes under 77 K and self-field conditions. The approach involves customized tensile and bending tests that clarify the critical current (I_c) response of the CC tapes under mechanical loads induced by tension and bending. This study measures the retained Ic values of commercially available GdBCO CC tapes under 250 MPa tensile stress and 40 mm bending diameter. Through experimentation, the study demonstrates the resilience of these tapes and their suitability for applications. By presenting a simplified stress-based analysis and a bending test of the tapes, the study contributes to effective quality assessment methods for the development of practical superconducting products.

• Journal of the Korean Recycled Construction Resources Institute
• /
• v.8 no.1
• /
• pp.49-55
• /
• 2020

In this study, the surface temperature of the roof green system using ALSRBA(Artificial Lightweight Soil Recycled with Bottom Ash) was measured in each season and the thermal property of the ALSRBA was investigated. As a result, it was certified that ALSBRA has superior thermal property than the usual artificial soil. In addition, The daily temperature range in each season was measured to investigate the thermal isolation property of EUS(Existing Unit System) and DUS(Developed Unit System). The result showed that the thermal isolation effect of EUS was lower than that of SPSS(Site-Place-Soil System), but thermal isolation effect of DUS was similar to that of SPSS because DUS has continuous ALSBRA layer by removing unit barrier.

• Korean Journal of Acupuncture
• /
• v.19 no.2
• /
• pp.35-39
• /
• 2002

Objective : The purpose of this study was to investigate the Effect of Acupuncture Stimulation of Sohae(H3) and Sobu(H8) Acupoint on Skin Temperature of Sochung Acupint(H9, the end acupoint of Heart Meridian). Sohae and Sobu acupoint has a property of water and fire in the Five agents on Heart Meridian. Methods : Subjects were four healthy oriental medical students volunteers(male, mean age-28). One group(two subjects) received acupuncture on Sohae acupoint(H3) and the other group(two subjects) on Sobu acupoint(H8) while resting. Skin temperature was measured on Sochung acupoint(H9) before, during, and after acupunture stimulation. Each test took 15minutes. The initial 5minutes were definded as BAS(Before Acupuncture Stimulation) period, the following 5minutes as DAS(During Acupuncture Stimulation) period, the last 5minutes as AAS(After Acupuncture Stimulation) period. This test was performed twice in order to increase the statistical authenticity. Results : Our result indicates that acupuncrue stimulation of Sohae acupoint(H3) decreased and Sobu acupoint(H8) increased skin temperature on Sochung acupoint(H9) in the DAS period. The changes remained throughout the AAS period. Our conculusion are that stimulaton of the Water and Fire property-acupoint(H3, H8) on Heart changes the skin temperature on Sochung acupoint on the same Heart Meridian. However this study has no authenticity because it had no regard for many factors effecting on the result and the result of the study was the very reverse of our expectation.

• Proceedings of the KIEE Conference
• /
• 2011.07a
• /
• pp.1262-1263
• /
• 2011

Sulfur hexafluoride is the most commly used insulation gas in electrical systems. Gas insulated systems are widely used in the electric power industry for transmission and distribution of electrical energy. When $SF_6$ was first discovered, the potential application was only considered for insulation because of good dielectric properties. But the widespread use of $SF_6$ gas by electric power and other industries has led to increase concentrations of $SF_6$ gas in the atmosphere. This concern as to possible effects on global warming because $SF_6$ is a potent greenhouse gas. That's why firstly we studied uniform and nonuniform field property by mixing $SF_6$ and N2 gas. This paper presents the dielectric strength and insulating property for particle contamination under $SF_6/N_2$ mixtures. Two types of mixed gases(50% $SF_6$_50%$N_2$, 20% $SF_6$_80%$N_2$) were applied. We performed tests for the length and shape of particle. Test gas pressure is from 0.3 to 0.7 Mpa. The study was conducted to develop environment-friendly insulating material for GIS that can reduce $SF_6$ gas and make a design criteria for mixtures.

• Journal of the Korean Mathematical Society
• /
• v.55 no.4
• /
• pp.763-783
• /
• 2018

In this paper, we study an Artinian point-configuration quotient having the SLP. We show that an Artinian quotient of points in $\mathbb{p}^n$ has the SLP when the union of two sets of points has a specific Hilbert function. As an application, we prove that an Artinian linear star configuration quotient $R/(I_{\mathbb{X}}+I_{\mathbb{Y}})$ has the SLP if $\mathbb{X}$ and $\mathbb{Y}$ are linear starconfigurations in $\mathbb{p}^2$ of type s and t for $s{\geq}(^t_2)-1$ and $t{\geq}3$. We also show that an Artinian $\mathbb{k}$-configuration quotient $R/(I_{\mathbb{X}}+I_{\mathbb{Y}})$ has the SLP if $\mathbb{X}$ is a $\mathbb{k}$-configuration of type (1, 2) or (1, 2, 3) in $\mathbb{p}^2$, and $\mathbb{X}{\cup}\mathbb{Y}$ is a basic configuration in $\mathbb{p}^2$.

• Journal of the Korean Wood Science and Technology
• /
• v.44 no.4
• /
• pp.526-538
• /
• 2016

Fumigants are used worldwide for control of biological agents that damage wooden cultural property. To establish a policy for fumigant use, biological evaluation of insects and microorganisms considering many factors is required. This study was performed to evaluate biological sensitivity and wood penetration of three fumigants applied for control of biological agents that damage wooden cultural properties in Korea. Among these, methyl bromide and ethylene oxide can control insects and fungi when exposed directly. However, they were unable to completely control biological agents within deeper parts of wood. Ethanedinitrile, which was developed as an alternative fumigant, exhibited outstanding wood penetration and biocidal efficacy. Further research involving various environmental conditions is warranted.

• Journal of Korea Foundry Society
• /
• v.23 no.5
• /
• pp.251-256
• /
• 2003

Effects of Ca addition on grain refinement, microstructure and mechanical properties of AZ31 Mg alloy were investigated. Due to Ca addition to Mg alloy (AZ31), the microstructure was refined, the quantity of $Mg_{17}Al_{12}$phase was reduced, and new $Al_2Ca$ phase was formed. The tensile property of AZ31 was increased with the minor addition of Ca, but was decreased rapidly over 0.2 wt.% of Ca content. The $Al_2Ca$ phase was considered to be detrimental to the mechanical property of AZ31 Mg alloy.

• The Transactions of the Korean Institute of Electrical Engineers D
• /
• v.49 no.1
• /
• pp.18-25
• /
• 2000

In the two-mass servo system driving a load through a flexible shaft, a shaft torsional vibration is often generated. PI controller has been generally used is speed control of such system because of the simplicity of structure and related theory. This paper presents the inertia ratio of the PI servo control system which can be designed by using optimal pole assignment method is fixed. Therefore, it's difficult to obtain the desired control characteristics for different systems only by PI control algorithm. To solve this problems the two-mass speed control system with PID controller is designed by using pole assignment method and an optimum PID parameters are derived by evaluating ITAE(Integral of time multiplied by the absolute error) performance index. But this design method has some problems due to a trade-off between the fast command following property and the attenuation of disturbances and vibrations. In this paper, 2-DOF PID control method which satisfies the command following property, the reduction of overshoot and the property of disturbance rejection at the same time is proposed. This is a practical speed controller using the desired value filter and the feedforward gain. From several simulations, it's clarified that the proposed 2-DOF PID controller is useful for the two-mass system, in comparison with the conventional PID controller.

• The KIPS Transactions:PartD
• /
• v.16D no.2
• /
• pp.185-190
• /
• 2009

The event sequence of the same type from a set of events having time property can be summarized in one event. But if the event sequence having an interval, It is reasonable to be summarized more than one in independent sub event sequence of each other. In this paper, we suggest a method of temporal data mining that summarizes the interval events based on Allen's interval algebra and finds out interval event association rule from interval events. It provides better knowledge than others by using concept of an independent sub sequence and finding interval event association rules.

• Journal of Radiopharmaceuticals and Molecular Probes
• /
• v.2 no.1
• /
• pp.17-21
• /
• 2016

Alkali metal fluoride sources (MFs) such as potassium fluoride (KF) have been widely used as a fluoride source in the nucleophilic displacement reaction. However, they have low solubility and nucleophilicity in most of the organic solvents. Bulky fluoride sources such as tetrabutylammonium fluoride (TBAF) were substituted for MFs to improve these properties. However, hygroscopic property of TBAF makes it less convenient for handling as well as its strong basic property can make the side-reaction occur. Recently, novel fluoride sources have been developed to solve these problems. In this paper, we would like to introduce coordinated fluoride sources as a new fluoride sources such as tetrabutylammonium tetra(t-butyl alcohol)-coordinated fluoride, crown ether metal complex fluoride, and various bulky alcohols coordinated fluoride complexes. In particular, bulky alcohol coordinated fluoride source could generated by the controlled hydrogen-bonded of fluoride with alcohols and these fluoride sources have better stability and reactivity with showing low hygroscopic property. The study of these fluoride sources will help to understand the characteristic of [$^{18}F$]fluoride for increasing the radiochemical yield in the [$^{18}F$]radiofluorination.