• Applied Chemistry for Engineering
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• v.8 no.2
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• pp.286-291
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• 1997

Taxol which is recognized as a powerful anticancer reagent was extracted from yew extract and separated by NP-HPLC (Normal-PhaseHigh Performance Liquid Chromatography). The experiments were performed in the isocratic mode with $5{\mu}l$ to $100{\mu}l$ injection volume and 1ml/min mobile phase flow rate. The major mobile phase was hexane and small amounts of ethanol, methanol, 1-propanol and isopropanol were added to change the retention behavior. Prior to a real sample, the artificial mixture of taxol, cephalomannine and 10-deacetyltaxol was tested. They are hard to be separated because of similar chemical structures. The experimental results showed that the proper composition of mobile phase for separating the three components was found 96% hexane and 4% ethanol(vol.%) or 96% hexane, 2% 1-propanol and 2% methanol(vol.%). Compared to the run time of 80 minutes for the binary system, the mixture was separated within 50 minutes with the less amount of mobile phase for the ternary system. Finally, $1{\mu}g$ of taxol was separated from yew tree extracts under the optimum operating conditions.

• Fire Science and Engineering
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• v.18 no.2
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• pp.12-19
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• 2004

The commercially available IG-541 extinguished agent composed of inert gases was developed for environmental protection. The extinguished agents were considered in terms of physical properties, efficient characteristic, environment, stability, and economical efficiency. The pure and mixture components of physical properties of $N_2$, Ar and $CO_2$ were chosen and compared. The physical properties of density, viscosity and surface tension of inert gases were plotted with the molar ratios of $N_2$/$CO_2$ and Ar/$CO_2$ in terms of a temperature. The extinguished agent in the composition of $N_2$, Ar and $CO_2$, 50/40/10 (mol %) showed relatively high density, low viscosity and moderate surface tension, therefore it was suitable for the alternative extinguished agents.

• Fire Science and Engineering
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• v.21 no.3
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• pp.33-40
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• 2007

The values of the AITs(Autoignition temperatures) for fire and explosion protection are normally the lowest reported. This study measured the AITs of ethylbenzene+n-hexanol and ethylbenzene+n-propionic acid Systems from ignition delay time(time lag) by using ASTM E659-78 apparatus. The AITs of ethylbenzene, n-hexanol and n-propionic acid which constituted binary systems were $475^{\circ}C,\;275^{\circ}C\;and\;511^{\circ}C$, respectively. The experimental ignition delay time of ethylbenzene+n-hexanol and ethylbenzene+n-propionic acid systems were a good agreement with the calculated ignition delay time by the proposed equations with a few A.A.D.(average absolute deviation).

• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.335-335
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• 2013

최근 다기능 소재의 개발이 필요함에 따라 서로 상반되는 2가지 이상의 물성을 동시에 구현할 수 있는 소재의 개발이 요구되고 있다. 4 성분계 물질을 단일 타겟으로 제조함으로써 다수의 타겟을 이용하는 기존 PVD 방법의 복잡성과 재형성 등의 문제점을 해결하고 다기능성을 구현할 수 있는 코팅막을 제조할 수 있게 된다. 본 연구에서는 제조된 4 성분계 모물질을 UBM 최근 다기능 소재의 개발이 필요함에 따라 서로 상반되는 2가지 이상의 물성을 동시에 구현할 수 있는 소재의 개발이 요구되고 있다. 4 성분계 물질을 단일 타겟으로 제조함으로써 다수의 타겟을 이용하는 기존 PVD 방법의 복잡성과 재형성 등의 문제점을 해결하고 다기능성을 구현 할 수 있는 코팅막을 제조할 수 있게 된다. 본 연구에서는 제조된 4 성분계 모물질을 UBM 스퍼터링법을 이용하여 질화 공정을 도출하였고 질소 함량에 따른 물리적 특성 및 박막의 특성에 대해 연구하였다. BMG (Bulk Metallic Glass) 타겟을 이용하여 마그네트론 스퍼터링법으로 박막을 코팅하였다. 시편은 Si wafer, SUS 그리고 부식 특성 평가를 실시하기 위하여 냉연강판을 사용하였다. 시편은 아세톤, 알코올로 각각 10분간 초음파 세척한 후 진공장비에 장착하여 Ar 분위기에서 글로우 방전으로 청정을 30분간 실시하였다. 시편청정이 끝나면 ~$10^{-6}$ Torr까지 진공 배기를 실시하고 Ar 가스를 주입하여 2.5 mTorr로 진공도를 유지하여 스퍼터링으로 박막 코팅을 실시하였다. 스퍼터링 파워는 약 0.6 kW (2.0 A)으로 고정하였고 질소 유량은 0~10 SCCM으로 변화시켜 BMG 박막을 코팅하였다. 질소가 첨가된 BMG 박막에서는 시편의 색상이 노란빛으로 나타났으며 이것은 타겟의 조성 중 가장 많이 함유되어있는 Zr이 질화되어 색상의 변화가 일어난 것으로 판단된다. BMG 코팅을 위해서 진공용기로 주입한 질소의 유량이 소량인 경우에도 BMG 코팅층에 비교적 많은 양의 질소가 존재하였고 일정량 이상에서는 BMG 코팅층에 존재하는 질소의 양이 포화되는 현상을 보였다. 질소 유량 3, 4 SCCM의 BMG 코팅층에서 ZrN (111), ZrN (200) Peak이 관찰되었다. BMG 코팅층의 경도 측정결과 Bias 50 V 인가 시 ~22 Gpa로 경도가 가장 높았다. BMG 코팅층의 내부식 특성을 평가하기 위해 염수분무 시험을 실시하였고 ~$10{\mu}m$의 두께를 갖는 BMG 코팅층에서 염수분무 시작 후 48시간 만에 적청이 발생하였다.

• Journal of the Korea institute for structural maintenance and inspection
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• v.20 no.1
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• pp.9-17
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• 2016

In this study, binary blended concrete mix with fly ash and ground granulated blast furnace slag was prepared according to 3 level of water reduction performance of chemical admixture (0%, 8% and 16%) and 3 level of water-cement ratio (40%, 45% and 50%) for evaluation of quality properties of binary blended concrete according to performance of chemical admixture. concrete mix was carried out repetition test of three times in order to secure the reliability. As a result, compressive strength according to performance of chemical admixture was found that difference of strength was about 20% occurred, chemical admixture was showed that a great influence on qualities of concrete. In addition, reflected the effect of performance of chemiacal admixture, prediction model equations for concrete compressive strength was proposed, it was found that more than 85% of the high correlation.

• Journal of the Korea Concrete Institute
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• v.20 no.2
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• pp.175-183
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• 2008

Domestically, application of High Flowing Self-Compacting Concrete (HSCC) is limited to building structures and it is difficult to find examples of application in civil infrastructural constructions. However, in the case of North America and Europe, by introducing precast and prestressed system, HSCC is being used for high-density reinforced bridge members. Hence it is assessed that broadening the utilization of HSCC into areas such as bridges and civil construction is required. Therefore in this research, to apply HSCC to high-density reinforced bridge members, ground granulated blast-furnace slag and fly ash were mixed in binary and ternary systems. Also the dynamical characteristics of HSCC, following 1st class regulations of Japan Society of Civil Engineers (JSCE), were assessed to enable application on high-density reinforced structures. The test results revealed ternary system mixture showed better mechanical characteristics than binary system mixture and the application on high-density reinforced precast bridge members seems possible.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.2
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• pp.1188-1194
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• 2014

The purpose of this study is to estimate Chloride Attack Resistibility and mechanical properties of quaternary concrete adding fly ash, blast-furnace slag, and silica fume. Compressive strength, modulus of elasticity, chloride migration coefficient, charge passed from Rapid chloride penetration test(RCPT), and immersion testing in 3% NaCl are tested. Chloride migration coefficient and charge passed of quaternary concrete measured $0.032{\times}10^{-12}m^2/sec$ and 650 coulomb at 17 weeks, which are in a permitted limit. Also in immersion test, depth of chloride penetration and maximum chloride ion of quaternary concrete measured 3.7 mm and $10.211kg/m^3$ respectively. From the results, quaternary concrete adding fly ash, blast-furnace slag, and silica fume denotes improvement of mechanical properties and chloride attack resistibility.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.15 no.2
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• pp.154-160
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• 1982

One dimensional unsteady heat conduction was studied on soybean curd as a water-protein-fat food system. This heterogeneous soybean curd could be treated as homogeneous material as for the unsteady heat conduction by 'effectiver' thermal diffusivity. Measurements were made with a apparatus designed and constructed by the author and also made with ice to establish the reliability, the reproducibility and the accuracy of the apparatus. It was found that the effective thermal diffusivity of soybean curd was substantially dependent on the fraction of protein and fat as well as water.

• Proceedings of the KAIS Fall Conference
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• 2009.05a
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• pp.863-866
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• 2009

Ethanol/3-methyl-1-butanol 계에 대하여 정온하 즉 50, 55, 60, 65, 70, 75 및 $80^{\circ}C$에서 2성분 기-액 평형측정치를 측정하였다. 측정된 기-액평형치의 액조성과 비휘발도의 대수치와의 관계를 직교좌표에 plot하면 직선이 이루어지고 온도변화에 대한 각각의 직선이 평형임을 확인하였다. Ethanol/3-methyl-1-butanol 계에 대한 추산식은 각각의 온도변화에 따라 나타내었고 이식들을 이용하여 추산식을 구하였다. 추산식으로부터 구한 추산치와 측정치를 비교 검토한 결과 Ethanol/3-methyl-1-butanol 계에서는 기상조성의 몰분율은 ${\pm}0.00051$[-]의 오차 범위에서 잘 일치하는 것으로 나타났고, modified UNIFAC방법은 실측치와 비교한 평균오차는 ${\pm}0.0022$[-]에서 추산하였다. 따라서 본 연구에서 제안한 추산법이 2성분계 기-액평형치를 추산하는 방법으로 타당함을 확인하였다.

• Journal of Korean Society of Environmental Engineers
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• v.37 no.3
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• pp.159-164
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• 2015

This study investigated the environmental risk for up-cycling of air-cooled ladle furnace slag (LFS) and evaluated the mortar compressive strength of binary and ternary blended cements using LFS of 3, 5, 10 wt%. Based on the Soil Environment Conservation Act standard, there was no environmental risk of the up-cycling of LFS. Results of mortar compressive strength assesment showed that the compressive strength of two blended cements using LFS of lower than 5 wt% was about 1.1 times superior to that of un-substituted cement (ordinary portland cement, OPC); however the compressive strength of those with LFS of 10 wt% decreased with 10% compared with that of OPC.