• Structural Engineering and Mechanics
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• 제54권4호
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• pp.725-740
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• 2015

This study presents critical buckling load optimization of the axially graded layered uniform columns. In the first place, characteristic equations for the critical buckling loads for all boundary conditions are obtained using the transfer matrix method. Then, for each case, square of this equation is taken as a fitness function together with constraints. Due to explicitly unavailable objective function for the critical buckling loads as a function of segment length and volume fraction of the materials, especially for the column structures with higher segment numbers, initially, prescribed value is assumed for it and then the design variables satisfying constraints are searched using Differential Evolution (DE) optimization method coupled with eigen-value routine. For constraint handling, Exterior Penalty Function formulation is adapted to the optimization cycle. Different boundary conditions are considered. The results reveal that maximum increments in the critical buckling loads are attained about 20% for cantilevered and pinned-pinned end conditions and 18% for clamped-clamped case. Finally, the strongest column structure configurations will be determined. The scientific and statistical results confirmed efficiency, reliability and robustness of the Differential Evolution optimization method and it can be used in the similar problems which especially include transcendental functions.

• 동아시아식생활학회지
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• 제12권3호
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• pp.241-248
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• 2002

The dried Prunus mume, an alkaline food abundant in organic acids (citric acid, malic acid and tartaric acid), has been largely used in both folklore remedies and Chinese herbal medicine for a long time. This study was performed to investigate the antimicrobial activity of the dried Prunus mume. The fractionation of the methanol extracts from Prunus mume was conducted using petroleum ether, chloroform, ethyl acetate and butanol, respectively. The antimicrobial activity of the Prunus mume extracts was then determined against food-borne pathogens using a paper disc method. The ethyl acetate extract showed the strongest antimicrobial activity against the eigth food-born pathogens used in this present study. Diaion HP 20 column chromatography was performed to remove some sugars that might inhibit the antimicrobial activity of Prunus mume. The strongest antimicrobial activity of ethyl acetate fraction of Prunus mume was shown against Staphylococus aureus. The growth inhibition curve was determined using ethyl acetate extracts of Prunus mume against Staphylococus aureus, which showed the growth inhibition up to 72 hours at 1,000 ppm concentration.

• 약학회지
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• 제28권2호
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• pp.69-77
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• 1984

Anti-coagulant activities of 25 species of medicinal plants which have been related to "blood" in ethnobotany, were evaluated by plasma recalcification time test. Among these, Artemisiae Herba showed the strongest activity. Its anti-clotting component was purified by using DEAE-cellulose, Sephadex G-75, and Sephadex LH-20 column chromatography. Its active compound has an average molecular weight of approximately $10^{4}$ and it was turned to be an acidic polysaccharide composed of galacturonic acid and rhamnose (7 : 2) by chemical analysis and spectral data.

• KSBB Journal
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• 제8권1호
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• pp.75-82
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• 1993

The inhibitory effect of cacao bean husk (CBH) extract on glucosyltransferase(GTasc) from Streptococcus mutans B13 was investigated. Water solube extract from CBH showeda sarong inhibitory effect (88-89%) on GTase from Streptococcus mutans Bl3. GTase inhibitors from sequential extraction by hot water or water-methanol had the strongest inhibition. Sources, fermentation, and types of solvents and fumigation processes did not influence the effect. These active compounds proved to be polyphones through acid hydrolytic analysis of the precipitates by ammonium sulfate or ethanol and proteinase K. It was also confirmed by additional column chromatography of Sephadex G-50, Sephadex LH-20 and DEAE-Sephdex A-50.

• 생약학회지
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• 제25권1호
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• pp.59-69
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• 1994

Polygonum aviculare L. was extracted by methanol and then fractionated systematically with solvents and column chromatographic method in order to isolate ingredients with anti-lipid peroxidation and liver protectective effects. Among these fractions, ethylacetate soluble part(MWE) showed the strongest in the anti-lipid peroxidation. Furthermore, the crude subtraction(MWE 4) with Rf value near 0.42, which is separated from MWE by column chromatography using a solvent system, inhibited the lipid peroxidation of rat liver in vitro. Moreover, MWE 4 decreased GOT, GPT and TBA value compared with control and suggested high protective effects against hepatotoxicity induced by carbon tetrachloride in mice. The active compounds in MWE 4 were assumed to be flavonoid glucosides.

• 한국소음진동공학회논문집
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• 제16권10호
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• pp.1074-1081
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• 2006

This paper deals with the dynamic stability analysis of clamped-hinged columns with constant volume. Numerical methods are developed for solving natural frequencies and buckling loads of such columns, subjected to an axial compressive load. The parabolic taper with the regular polygon cross-section is considered, whose material volume and column length are always held constant. Differential equations governing both free vibrations and buckled shapes of such columns are derived. The Runge-Kutta method is used to integrate the differential equations, and the Regula-Falsi method is used to determine natural frequencies and buckling loads, respectively. The numerical methods developed herein for computing natural frequencies and buckling loads are found to be efficient and robust. From the numerical results, dynamic stability regions, dynamic optimal shapes and configurations of strongest columns are reported in figures and tables.

• 약학회지
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• 제31권1호
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• pp.33-39
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• 1987

In order to elucidate the defence mechanism of Cyprinus carpio nudus to Clonorchis sinensis, clonorchicidal substance in the epidermal mucus of this fish was isolated by silica gel column and thin layer chromatography and analyzed for its chemical nature by UV, IR and NMR-spectroscopy. The epidermal mucus of the fish was extracted by ethyl ether and separated into 2 fractions by column chromatography using petroleum ether/chloroform(30/70,v/v) as first solvent and methanol as second solvent. The second fraction with greyish white colour showed clonorchicidal effect. The second was again fractionated into greyish white precipitate and clonorchicidal greenish yellow supernatant fraction, by adding petroleum ether and standing the mixture for 5 days at $5^{\circ}C$. The latter was divided into 7 fractions in column chromatography with acetone/ benzene (10/90, v/v) as carrier. The fraction on equivalent to the spot of Rf. 0.225 value among them disclosed the strongest clonorchicidal effect. By this purification procedure, clonorchicidal substance was purified 154-fold with 0.9% yield from the mucus of the fish, and 10mg of the final fraction killed tne metaceicariae in 22 min. Infra red, nuclear magnetic resonance and ultraviolet spectrometric analysis of the purified substance revealed that the substance is linoleic acid. According to the results of the present studies it seemed that this fish could not be proper intermediate host of Clonorchis sixensis, and that defence mechanism of this fish to the worm seems to be correlated with clonorchicidal substance in epidermal mucus.

• 한국식품영양학회지
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• 제11권1호
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• pp.36-40
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• 1998

장내 유해세균에 대한 세균성 장내 질환치료와 관련된 한약재를 항균활성 검색을 통해 우수한 효과가 인정된 빈랑을 선정하고 혐기적 broth system에서 각 용매별 분획물의 6종의 장내 유해세균에 대한 항균활성을 측정하였으며 그 항균물질을 column chromatography법에 의해 부분 정제하였다. 빈랑의 경우, n-hexane을 제외하고 각 분획에서 뛰어난 항균력을 나타내었으며, 특히 ethylacetate 분획의 항균활성이 뛰어났다. 빈랑의 ethylacetate 분획은 Sephadex G-200 clumn chromatography에 의한 30기 분획 중 5번에서 7번까지의 분획에서 강한 항균활성을 나타내었으며 Silica gel column chromatography에 의한 40개 분획 중에서 20번 분획에서 항균활성을 보였다.

• 한국강구조학회 논문집
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• 제19권1호
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• pp.99-106
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• 2007

이 논문은 일정체적 양단고정 기둥의 정 동적 최적형상에 관한 연구이다. 기둥의 단면은 정다각형이며, 단면깊이는 포물선으로 변화하는 변단면이다. 축방향 압축하중이 작용하는 기둥의 고유진동수 및 좌굴하중을 산정하는 수치해석 기법을 개발하였다. 그러한 기둥의 자유진동을 지배하는 미분방정식을 유도하고 Runge-Kutta법과 Regula-Falsi법을 이용하여 고유진동수를 산정하였다. 수치해석의 결과로부터 얻어진 하중-고유진동수 사이의 관계를 이용하여 기둥의 좌굴하중을 산정하였다. 기둥의 변수연구를 통하여 동적 안정영역, 동적 최적형상 및 최강기둥의 형상을 산출하였다.

• Preventive Nutrition and Food Science
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• 제2권3호
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• pp.191-196
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• 1997

The antioxidative activity of seven different acylated anthocyanin pigments isolated from grape, sweet potato, eggplant and red cabbage was evaluated bvy using linoleic acid autoxidation and rat liver microsomal systems. The acylated anthocyanins were isolated and purified by Amberlite SAD-7, ODS and Sephadex LH-20 column omatography, and preparative HPLC. Most of acylated anthocyanisns exhibited antioxidative activity as strong as $\alpha$-tocoperol, and especially peonidin3-O--(6-O-trans-caffeyl)-2-O-(6-O-trans-feuloylglucopyranosyl)-$\beta$-D-glucopyranosyl-5-O-$\beta$-D-glucopyranoside from purple sweet potato showed the strongest activity, comparable to BHA (not significant, p<0.05) in the linoleic acid system. Meanwhile, two acylated anthocyanins from the pericarps of grape and eggplant inhibited considerably the MDA formation from rat liver microsomal lipid peroxidation induced by FeSO$_4$/$H_2O$$_2$. In particular, malvidin 3-O-(6-O-p-coumaroyl)-$\beta$-D-glucopyranosde from grape pericarps showed the strongest antioxidant activity, comparable to $\alpha$-tocopherol (not significant, p<0.05). These results suggest that the acylated anthocyanins from fruits and vegetables can be used as potential dietary ntioxidants and natural colorants.