• Journal of Applied Biological Chemistry
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• 제65권4호
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• pp.343-348
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• 2022

백지는 산형과(Umbelliferae)에 속하는 구릿대(Angelica dahurica)의 뿌리를 건조한 것으로, 다양한 약리작용을 하는 것으로 알려져 예로부터 한약재로 사용되어 왔다. 백지의 대표적인 활성 성분인 coumarin을 포함하여 다양한 성분이 알려져 있으며, 최근 백지의 다양한 생리활성이 보고되고 있다. 본 연구는 백지를 건강기능식품의 기능성 원료로 활용하고자, 백지의 지표성분 설정 및 이에 대한 UPLC 분석법을 확립하여 분석법 유효성 검증을 실시하였다. 백지의 지표성분으로는 oxypeucedanin hydrate, byakangelicol, oxypeucedanin, imperatoin, phellopterin, isoimperatorin의6종을 설정하였다. 분석법 유효성 검증은 특이성, 직선성, 검출한계, 정량한계, 정확성, 정밀성 등의 항목을 이용하여 확인하였다. 본 시험법에서 지표성분 6종은 서로 간섭없이 분리되어 특이성을 확인하였고, 결정계수의 값도 0.999 이상으로 나타나 높은 직선성을 나타내었다. 분석법 유효성 검증 결과, 지표 성분 6종의 RSD는 5% 이하로 나타났으며 90-110%의 범위의 회수율을 나타내 높은 정확성과 정밀성이 있는 것을 확인할 수있었다. 이러한 결과는 UPLC를 이용한 백지의 지표성분 분석법이, 새롭게 제시한 6종에 대해 적합한 동시분석 분석법임을 나타낸다. 따라서, 본 연구를 통하여 확립된 백지의 지표성분 분석법이 향후 백지(구릿대)의 건강기능식품 기능성 원료 개발을 위한 기초자료로 활용될 것으로 기대된다.

• 한국환경농학회지
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• 제42권2호
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• pp.139-151
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• 2023

Sulfonylurea herbicides are widely used in agriculture because they have a long residual period and high selectivity. An analytical method was developed using QuEChERS (Quick, Easy, Cheap, Effective, Rugged, and Safe) technique for simultaneous determination of sulfonylurea herbicide residues in agricultural products by liquid chromatography tandem mass spectrometry and for establishment MRL (Maximum Residue Limit) of those herbicides in Korea. Extraction was performed using acetonitrile containing 0.1% formic acid with MgSO₄ (anhydrous magnesium sulfate) and NaCl (sodium chloride) and the extract was cleaned up using MgSO₄ and C₁₈ (octadecyl). The matrix-matched calibration curves were composed of 7 concentration levels from 0.001 to 0.25 mg/kg and their coefficients of determination (R²) exceeded 0.99. The recoveries of three spiking levels (LOQ, 10LOQ, 50LOQ, n=5) were in the range of 71.7-114.9% with relative standard deviations of less than 20.0% for all the five agriculture products. All validation values met criteria of the European Union SANTE/11312/2021 guidelines and Food and Drug Safety Evaluation guidelines. Therefore, the proposed analytical method was accurate, effective, and sensitive for sulfonylurea herbicide residues determination in agricultural commodities.

• 분석과학
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• 제22권4호
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• pp.326-335
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• 2009

계란 중에 잔류하는 6 종의 글루코코티코이드 약물을 극미량으로 분석하는 방법이 개발되었다. 동시분석을 위한 시료 추출방법과 정제방법을 확립하였으며 액체 크로마토그래프와 질량분석기의 최적화 조건을 확립하였으며, 글루코코티코이드를 분석하기 위해서는 5 g의 계란에 초산 완충용액을 사용하여 시료의 pH를 5.2로 조절한 후 효소 가수분해를 위해 Helilx pomatia를 사용하였다. 혼합물을 원심분리하여 20 mL n-헥산으로 두 번 추출하였다. 다시 HLB 카트리지에서 메탄올에 의한 추출이 이루어진 후 연속해서 실리카 카트리지에서 메탄올/에틸아세테이트를 사용하여 정제하였다. 분석물질은 역상 HPLC/ESI-MS/MS로 분석하였으며 ESI는 음이온 모드를 사용하였다. 검정곡선의 상관계수는 0.99 이상을 나타내었고 검출한계는 $0.09-0.17{\mu}g/kg$ 이었으며 회수율은 55.7-69.8%이었다. 바탕 계란 중에서 실험된 유효성 검증방법에 근거하여 확립된 분석법은 계란 중 글루코코티코이드를 수 ${\mu}g/kg$ 농도까지 검출하는데 사용될 수 있을 것이다.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 춘계학술대회논문집E
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• pp.582-587
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• 2001

A numerical method using FLUENT code was employed to investigate fluid drag and lift forces on a cylinder in a group of circular cylinders, subjected to a uniform cross flow. The cylinders can be arranged in tandem or in a staggered arrangements relative to the free stream flow. A vortex street behind the cylinder pairs or jets between the cylinders forms according to the arrangements. Vibration on a cylinder can occurs due to vortex shedding, fluid-elastic stiffness and wake galloping. The flow is first investigated and then the forces acting on the cylinder are calculated. The lift and drag forces on an elastically mounted cylinder in the wake of an upstream fixed cylinder arise from the mean flow plus velocity and pressure gradients in the wake. The analytical results of two staggered cylinder were compared with the existing experimental ones for validation of the present method. The analytical results of the forces were in good agreement with the experimental ones. The present method can be used for the analysis of the fluid induced vibration where the group of circular cylinders are subjected to a cross flow.

• 한국자동차공학회논문집
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• 제8권4호
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• pp.42-50
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• 2000

Drop size distribution of an air-assisted fuel injector(AAFI) was investigated. Influence of parameters such as ambient air density supply pressure and air-liquid mass ratio(ALR) was examined through both measurement and analysis. The Sauter mean diameter$D_{32}$ varied from 9 to 25$\mu$m throughout all experimental conditions. An empirical correlation for droplet size was obtained. Analytical correlations for predicting $D_{32}$ with respect to operating conditions were also derived through energy consideration and introduction of a simplified model of the from the empirical fitting was adapted to the original equation the proposed correlation in this study matched more closely with measured results. The current correlation exhibited a favorable study matched more closely with measured results. The current correlation exhibited a favorable prediction for $D_{32}$ compared to that by the empirical correlation at selected experimental conditions so that it may be used to predict atomization performance of the AAFI at operating conditions which was not covered in the measurements. After validation the analytical equation was applied to survey the feasible operating conditions for gasoline direct injection application.

• 소성∙가공
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• 제16권7호
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• pp.516-520
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• 2007

As the springback of sheet metal during unloading nay cause deviation from a desired shape, accurate prediction of springback is essential for the design of sheet stamping operations. On the removal of the applied load the specimen loses its elastic strain by contracting around the contour of the block, the radius $\rho$ can be determined by the residual differential strain. Therefore in this study the springback estimated by the residual differential strain is experimentally validated through the comparison with those obtained by U-bending test. The springback characteristics of two analytical models are also estimated at various processing conditions such as thickness, curvature of radius and drawing strain. The model based on residual differential strain has an applied transition strain where the springback undergoes a dramatic decrease. Both models show that springback decreases with increased strip thickness and with decreased radius of curvature. For no applied tension, the model based on residual differential strain predicts more springback as compared to the moment based model.

• 대한수의학회지
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• 제48권1호
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• pp.33-38
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• 2008

In veterinary medicine amitraz has been used as an insecticide to eliminates mites, lice, and ticks in dogs, cats, goats, swine and cattle. The objective of present study was to developed an analytical method using one-step extraction and determination of the amitraz in veterinary drugs by liquid chromatography (LC). The amitraz was analyzed by LC equipped with Waters XTerra RP18 ($4.8{\times}250mm;\;5{\mu}m;\;Waters,\;USA$) analytical column, using 75% acetonitrile (acetonitrile/D.W; 75/25) at 1.0 ml/ min. The UV-VIS detection of amitraz was made at 290 nm. Calibration graphs were linear with very good correlation coefficients ($r^2>0.9999$) from $80{\sim}120{\mu}g/ml$. The limit of detection was $0.09{\mu}g/ml $ and limit of quantification was $0.27{\mu}g/ml $. The method showed good intra-day precision (CV 0.05~0.09%) and inter-day precision (CV 0.06~0.18%).

• Applied Biological Chemistry
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• 제46권4호
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• pp.271-279
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• 2003

국가간 혹은 기관간의 통합되고, 상호 인정할 수 있는 분석법의 기본 지침이 확립되면, 서로 다른 실험 여건이라 할지라도 공통된 실험 지침에 따라 수행된 연구 및 조사 결과를 생산할 수 있고, 결과를 비교 분석할 때 오류를 줄임으로써 국가 정책 수립을 위한 과학적이고 정확한 자료제공을 할 수 있다. 현재, 우리나라는 분석과 관련한 통합된 우수실험실규범(Good Laboratory Practice) 운용체계나, 정부기관에서 발행된 각종 공정 시험법 내 기초적인 기준(criteria)이 미흡하며, 용어나 그 용어의 정의에 대한 통일성을 찾기가 쉽지 않다. 따라서 신뢰성 있는 분석결과의 상호인정을 위해서 전문가들로 구성된 통합 지침의 확립이 절실히 요구된다. 이런 이유로 본 총설에서는 정량분석의 기초인 검량선 작성법에 대해 ISO, ACS, ASTM, AOAC, CODEX 및 관련 서적과 연구 논문을 통해 지침과 실례 등을 살펴보고 일상적인 분석업무 중 발생하는 오류 등에 대하여 설명하였다.

• 분석과학
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• 제27권4호
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• pp.196-200
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• 2014

국가 공정서 중 하나인 대한민국약전외의약품 기준에는 디페메린염산염의 정량법으로 유해시약인 아세트산수은을 사용하는 비수적정법이 수재되어 있다. 본 연구에서는 디페메린염산염의 환경 친화적인 대체 시험법으로 보다 안전하고 효율적인 친환경용매인 에탄올을 사용하는 중화적정법을 개발하고, 분석법을 검증하였다. 디페메린염산염의 직선성은 상관계수(r)가 0.999 이상을 나타내었고, 정확도는 99.10~99.71%, 정밀도는 0.64% 이하로 나타났다. 개발된 시험법은 대한민국약전외의약품 기준의 개정에 기여가 될 것이다.

• 한국연소학회지
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• 제13권1호
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• pp.23-30
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• 2008

An analytical expression for the turbulent burning velocity is derived from the asymptotic zone conditional transport equation at the leading edge. It is given as a sum of laminar and turbulent contributions, the latter of which is given as a product of turbulent diffusivity in unburned gas and inverse scale of wrinkling at the leading edge. It was previously shown that the inverse scale is equal to four times the maximum flame surface density in the wrinkled flamelet regime [1]. The linear behavior between $U_T$ and u' shows deviation with the inverse scale decreasing due to the effect of a finite flamelet thickness at higher turbulent intensities. DNS results show that $U_T/S^0_{Lu}$ may be given as a function of two dimensionless parameters, $u'/S^0_{Lu}$ and $l_t/\delta_F$, which may be transformed into another relationship in terms of $u'/S^0_{Lu}$, and Ka. A larger $l_t/{\delta}_F$ or a smaller Ka leads to a smaller scale of wrinkling, hence a larger turbulent burning velocity in the limited range of $u'/S^0_{Lu}$. Good agreement is achieved between the analytical expression and the turbulent burning velocities from DNS in both wrinkled and thickened-wrinkled flame regimes.