• KSBB Journal
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• 제23권1호
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• pp.96-100
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• 2008

한국산 녹차로부터 HPLC On-line $ABTS^{+}$ screening기법을 사용하여 catechin compounds의 특성중의 하나인 항산화활성을 빠르게 분석하였으며 녹차로부터 catechin compound의 추출을 다양한 온도와 시간의 추출방법을 적용하였다. 전 처리한 추출액에 포함된 catechin compounds을 분석하고 최적의 추출조건을 실험적으로 모색하였다. 실험결과에 의하면 추출온도 $60^{\circ}C$, 추출시간 3분으로 추출한 시료가 항산화활성이 가장 우수하였다.

• Structural Engineering and Mechanics
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• 제83권1호
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• pp.19-29
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• 2022

The angle steel frame confined concrete columns (ASFCs) are an emerging form of hybrid columns, which comprise an inner angle steel frame and a concrete column. The inner angle steel frame can provide axial bearing capacity and well confining effect for composite columns. This paper presents the experimental and theoretical studies on the seismic behaviour of ASFCs. The experimental study of the 6 test specimens is presented, based on the previous study of the authors. The theoretical study includes two parts. One part establishes the section analysis model, and it uses to analyze section axial force-moment-curvature. Another part establishes the section moment-curvature hysteresis model. The test and analysis results show that the axial compression ratio and the assembling of steel slabs influence the local buckling of the angle steel. The three factors (axial compression ratio, content of angle steel and confining effect) have important effects on the seismic behaviour of ASFCs. And the theoretical model can provide reasonably accurate predictions and apply in section analysis of ASFCs.

• 분석과학
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• 제19권2호
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• pp.142-148
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• 2006

고속액체크로마토그라피를 이용하여 어류 중 말라카이트그린 및 류코말라카이트그린의 최적 분석조건을 확립하고 국내유통 수산식품을 분석하였다. 균질화한 시료를 아세토니트릴로 추출하고 디클로로메탄에 분산시켜 농축 후 메탄올에 용해하여 분석하였다. 이동상으로는 아세토니트릴과 아세테이트 완충용액의 혼합용액을 사용하였으며, 검출파장은 620 nm이었다. 류코말라카이트그린을 말라카이트그린과 동시에 분석하기 위하여 산화납(IV) 컬럼을 분석컬럼 뒤에 연결하여 류코말라카이트그린을 말라카이트그린으로 산화하였다. 상관계수($r^2$)는 말라카이트그린이 0.9989, 류코말라카이트그린이 0.9995이었으며, 검출한계는 신호대 잡음비 3 이상에서 말라카이트그린과 류코말라카이트그린의 합으로서 0.005 mg/kg이었다. 회수율은 84~98%(CV는 3~16%)로 만족할 만한 수준이었다. 분석결과 잉어 및 붕어 서료에서 류코말라카이트그린이 검출되었다.

• 약학회지
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• 제53권2호
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• pp.51-59
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• 2009

Quantitative analysis of (+)-catechin (C), (-)-epigallocatechin (EGC), (-)-epicatechin (EC), (-)-epigallocatechin gallate (EGCG), (-)-epicatechin gallate (ECG) and caffeine in commercial green tea was carried out by HPLC employing gradient elution of 0.1% acetic acid and acetonitrile on ODS column. The optimized HPLC method provided satisfactory linearity, accuracy and precision. The relationship between the concentration of the components and cultivated region of the commercial green tea was not significant, while the concentration of EGCG, ECG and caffeine decreased significantly in the later harvested green tea samples (p<0.01). Multivariate analysis of the components was performed in order to characterize and evaluate the cultivated region and harvest period-related variation. Hierarchical clustering and discriminant analysis were applied to classify the geographical and seasonal origins of the green tea samples. The classification accuracy of the cultivated region and harvest period by discriminant analysis was 95% and 91%, respectively, indicating that this method could be reliable and convenient for the quality control of herbal products with different origin.

• Fisheries and Aquatic Sciences
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• 제9권3호
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• pp.115-117
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• 2006

A micro algal growth-enhancing polysaccharide compound was isolated from the green alga Monostroma nitidum using water extraction, molecular fractionation, a DEAE-cellulose column, and fast protein liquid chromatography using a Superose-12 column. The yield of the compound from the seaweed powder was 8.3$\times$l0$^{-3}$%. At 2 mg/mL concentration, the polysaccharide enhanced Tetraselmis suecica cell growth in f/2 medium by approximately 160%.

• 대한기계학회논문집A
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• 제32권2호
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• pp.148-161
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• 2008

A volume integral equation method (VIEM) is used to calculate the plane elastostatic field in an isotropic elastic half-plane containing multiple isotropic or anisotropic inclusions subject to remote loading. A detailed analysis of stress field at the interface between the matrix and the central inclusion in the first column of square packing is carried out for different values of the distance between the center of the central inclusion in the first column of square packing of inclusions and the traction-free surface boundary in an isotropic elastic half-plane containing multiple isotropic or anisotropic inclusions. The method is shown to be very accurate and effective for investigating the local stresses in an isotropic elastic half-plane containing multiple isotropic or anisotropic inclusions.

• 한국임상수의학회지
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• 제11권1호
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• pp.389-392
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• 1994

To purify transforming growth factor type beta(TGF-$\beta$) in canine platelets, Sephadex G-75 gel filtration and semipreparative HPLC were carried out. The column of $2.0 {\times}120cm$ was used for gel filtration and one inch semipreparative column filled with SP-Toyopeal for HPLC. Electrophoresis and bioassay using African green monkey kidney cell were used for identification of TGF-$\beta$ Crude TGF-$\beta$ of 2.75mg was extracted from 5.2g of the platelets by the treatment of acid/ethanol. In gel filtration of crude TGF-$\beta$, 4 peaks were observed at the detection of spectrophotometer at 280nm. Electrophoresis and bioassay identified the 3rd peak TGF-$\beta$. Linear gradient elution from 0 to 3M NaCl in sornipreparative HPLC showed TGF-$\beta$ at 1.5M NaCl. Gel filtration was less expensive and useful method for the purification of TGF-$\beta$.

• Food Science and Biotechnology
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• 제14권1호
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• pp.89-93
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• 2005

Squalene synthase (SQS) inhibitors were screened from various plants and food extracts. Effective SQS inhibitor was purified from fermented soybean paste using ethanol extraction, HP-20 column chromatography, ethyl acetate extraction, silica gel column chromatography, and crystallization. Through UV spectrometry, $^1H$ NMR, $^{13}C$ NMR, and mass spectrometry, SQS inhibitor was identified as daidzein with molecular mass of 254 and molecular formula of $C_{15}H_{10}O_4$. Daidzein showed $IC_{50}$ value of 50 nmol/L against SQS, confirming its potential as therapeutic agent for hypercholesterolemia.

• 한국환경과학회지
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• 제13권12호
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• pp.1059-1065
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• 2004

Bio sparging experiments were conducted in a laboratory column to investigate the potential removal of diesel contaminated groundwater. The objectives in this study were (a) to determine the extent of diesel degradation in laboratory columns under supplement of nutrient; (b) to determine the effect of variation of air flow in the removal of diesel and (c) to evaluate the potential enhancement of diesel degradation as a function of temperature. Our results showed that the nutrient supplement and higher air flow greatly enhanced diesel degradation. However, the variation of water temperature examined slightly increased degradation rate of diesel fuel.

• 국제초고층학회논문집
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• 제9권4호
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• pp.377-386
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• 2020

Beginning a few decades ago, Baku, the capital city of Azerbaijan, has experienced a dramatic construction boom that is revitalizing its skyline. The expansive growth looks to uphold the historic past of Baku as a focal point within the Caspian Sea Region while also evoking aspirations for a city of the future. With superstructure complete and interiors progressing, the Ministry of Taxation (MOT) tower is the latest addition to the city, with its stacked cubes twisting above a multi-level podium at the base. Each cube is separated by column-free green roof terraces, creating unique parametric reveals of the developing surroundings. Aside from MOT's stunning shape, its geolocation resulted in unusually high wind loads coupled with high seismic hazards for a tower of its height. In addition, limitations on possible structural systems required stepping away from a typical prescriptive code-based approach into one that utilized Performance-Based Design (PBD) methods. This paper presents the numerous structural challenges and innovations that allowed the design of a new icon to be realized.