• Journal of the Korean Crystal Growth and Crystal Technology
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• v.15 no.5
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• pp.188-192
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• 2005

High $T_c(Y_{0.5}Nd_{0.25}Sm_{0.25})Ba_2Cu_3O_y[(YNS)-123]$ superconductors with/without $CeO_2$ additive were systematically investigated by the zone melt growth process in air. Cylindrical green rods of (YNS)-123 oxides were fabricated by cold isostatic pressing (CIP) method using rubber mould. A sample prepared by this method showed well-textured microstructure, and $(Y_{0.5}Nd_{0.25}Sm_{0.25})_2BaCuO_5[(YNS)211]$ nonsuperconducting inclusions were uniformly dispersed in large $(Y_{0.5}Nd_{0.25}Sm_{0.25})Ba_2Cu_3O_y$[(YNS)123] superconducting matrix. In this study, optimum melting temperature and growth rate were $1100^{\circ}C$ and 3 mm/hr, respectively. The directionally melt-textured (YNS)-123 sample with $CeO_2$ additive showed an onset critical temperature $(T_c)\;T_c{\geq}93K$ and sharp superconducting transition.

• The Korean Journal of Applied Statistics
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• v.27 no.1
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• pp.13-20
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• 2014

Phase I Clinical Trials estimate a Maximum Tolerated Dose(MTD). In this paper, an MTD estimation method applied stopping rule is proposed for Phase I Clinical Trials. The suggested MTD estimation method is compared to the Continual Reassessment Method(CRM) method using a Monte Carlo simulation study.

• Progress in Superconductivity and Cryogenics
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• v.8 no.3
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• pp.27-31
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• 2006

We propose a replication method to solve the problem of large percent failure in texturing processes of coated conductors. This problem is due to the individual texturing process for each coated conductor that is very long tape having no single defect spot. We tested two different methods of replication process that are based on a well-textured Ni template. First method has structure of Ni/BaO/STO/$CeO_2$/SmBCO/Ag. So BaO layer is dissolved in water that we can separate STO/$CeO_2$/SmBCO/Ag layers. In this processing, the property of STO is conserved but the superconductivity of SmBCO is deteriorated. So we can consider another method. Second method has structure of template(STO)/BaO/STO/Pt/STO. After dissolving BaO then we deposited YBCO. The result of these experiments showed the feasibility of replication.

• Proceedings of the Korean Magnestics Society Conference
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• 1999.10a
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• pp.68-69
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• 1999

• Journal of Magnetics
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• v.3 no.4
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• pp.99-104
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• 1998

The $ Sm_2Fe_{17}N_x $materials were prepared by the combination consisting of the HDDR (hydrogenation, disproportionation, desorption, and recombination) process and nitrogenation or by the conventional way consisting of nitrogenation only, and the magnetic and thermomagnetic properties of the materials were investigated. The magnetic characterisation of the prepared $ Sm_2Fe_{17}N_x $ materials was performed using a VSM. Thermal stability of the materials was evaluated using a DTA under Ar gas atmosphere. The thermomagnetic characteristics of the materials were examined using a Sucksmith-type balance. The previously HDDR-treated Sm2Fe17parent alloy was found to be nitrogenated more easily compared to the ordinary $ Sm_2Fe_{17}N_x $alloy. The $ Sm_2Fe_{17}N_x $ material produced by the combination method showed a high coercivity (12.9 kOe) even in the state of coarse particle size (around 60 ${\mu}{\textrm}{m}$). It was also revealed that the $ Sm_2Fe_{17}N_x $ material produced by the material produced by the combination showed an unusual TMA tracing featured with a low and constant magnetisation at lower temperature range and a peak just before the Curie temperature. This thermomagnetic characteristic was interpreted in terms of the competition between two counteracting effects; the decrease in magnetisation due to the thermal agitation at an elevated temperature and the increase in magnetisation resulting from the rotation of magnetisation of the fine grains comparable to a critical single domain size due to the decreased magnetocrystalline anisotropy at an elevated temperature.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2019.11a
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• pp.267-267
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• 2019

The purpose of this study is to understand the risk of chemical product, Styrene Monomer(SM), shipped in a vessel. SM is harmful chemical product which can make injury, explosion and/or fire in a vessel. The understand of SM risk is very important to protect seafarer's body and vessel safety. This research can be expected that the understanding of SM risk by a seafarer's to prevent accidents by SM explosion/fire. In this study we used event tree analysis method using chemical reaction cased by explosion. As a result, we founded various chemical reaction and visualization for explosion path.

• Journal of Broadcast Engineering
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• v.20 no.1
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• pp.3-15
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• 2015

Recently terrestrial digital broadcasting systems have experienced a growth with the demand of high data rate. In order to meet such demand, the MIMO technology has received a wide attention. This paper proposes a pre-coding method, which provides high space channel correlation for the improved performance over terrestrial broadcasting channels when the polarized $2{\times}2$ MIMO SM is adopted for DVB-NGH systems. When signals with two different modulation orders are transmitted through two antennas, a method that is based on non-uniform power is also proposed for improved reception performance. To optimize the proposed method, phase shifting values for the pre-coding method and appropriate unequal power ratio are obtained. These obtained parameters are applied to a terrestrial broadcasting system, and then the performance improvement over the conventional SM is shown through computer simulations.

• Journal of Broadcast Engineering
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• v.19 no.6
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• pp.826-835
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• 2014

Recently, spatial modulation (SM) schemes are considered to improve the reception performance in spatially correlated channel environments. SM schemes utilize a switching method between multiple transmitters to reduce the correlation among multiple transmitters to reduce the correlation of each received signals and can support transmission additional bits using antenna combinations without extra bandwidth. Therefore, SM schemes can overcome correlation interference of conventional MIMO in urban wireless channels. However, the performance comparisons between SM schemes are not yet performed in correlated urban wireless channels. In this paper, some representative SM schemes are compared and a suitable SM-MIMO system in correlated urban wireless channels is proposed.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.24 no.1
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• pp.27-31
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• 2011

ZnS:Mn yellow phosphors doped with Sm for white light emitting diodes were synthesized by solid state reaction method. These sample showed the characteristic X-ray diffraction patterns for main peak (110) of ZnS:Mn,Sm. Photoluminescence excitation spectra originated from $Mn^{2+}$ were ranged from 450 nm to 500 nm. The yellow emission at around 580 nm was associated with $^4T_1{\rightarrow}^6A_1$ transition of $Mn^{2+}$ ions in ZnS:Mn,Sm phosphors. The highest photolum inescence intensity of the phosphors under 405 nm and 450 nm excitation was obtained at Sm concentration of 1 mol%. The enhanced photoluminescent intensity in the ZnS:Mn,Sm phosphors was interpreted by energy transfer from Sm to Mn. The highest luminescent intensity of white LED was obtained at the epoxy-to-yellow phosphor ratio of 1:3. At this ratio, the CIE chromaticity of the white LED was X=0.3886 and Y=0.2928.

• Fire Science and Engineering
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• v.28 no.5
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• pp.52-57
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• 2014

When structural elements of steel framed structures are exposed to fire situations, the structural stability begins to decrease due to dislocation of substantial. The increase of the beam length causes an additional stress and deflection. These can be serious factors to cause a severe failure of structures. To improve the fire resistance of beams, prevention of the heat from a fire by coating with fire protection material is essential for beams. The FR 490 was developed to enhance fire resistance compared with SM 490 steel. However, the fire resistance of FR 490 H-beams has not been evaluated by analysis method since it was developed. In this paper, materials properties in high temperature and a heat transfer and thermal stress theory were used in the evaluation of the fire resistance of FR490 H-beams. The fire resistance of FR490 steel beams was compared with that of SM490 beams. The comparison verified that the structural stability of FR490 beams at high temperature was superior to that of SM490 beams.