• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2010년도 제35회 추계학술대회논문집
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• pp.321-327
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• 2010

마이크로 크기의 단일 알루미늄 해석을 위한 간단한 모델을 작성하고, 현상의 주요 파라메터를 도출하는 연구를 수행하였다. 금속 입자의 연소는 점화와 준정상상태의 연소 단계로 구성하였고, 각 단계는 액적 연소의 경우와 유사하게 보존 및 이송 방정식들을 사용하여 모사되었다. 모델은 기존의 실험 데이터와의 엄격한 비교를 통해 신뢰성을 검증하였고, 이 과정에서 현상의 주요 변수를 도출하여 그 영향을 평가하였다. 주요 변수로는 초기 입자크기, 산화 피막 두께, 대류 열전달의 유무, 외기온도, 압력 등이 선정되었고, 간단한 열역학적 모델임에도 불구하고 정량적으로 실험 데이터와 유사하게 각각의 파라메터의 영향을 평가할 수 있음을 확인하였다.

• 한국식품과학회지
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• 제53권6호
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• pp.682-687
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• 2021

The purpose of this study was to validate a high-performance liquid chromatography (HPLC) method for the quantitative analysis of quercetin in various foods. The method was based on HPLC-UV (360 nm). The method was validated using candy, beverage, and sausage which were tested for specificity, linearity, limit of detection (LOD), limit of quantification (LOQ), precision, and accuracy, and the measurement uncertainty was assessed. Matrix-matched calibration was also applied. The calibration curves (0.5-50 mg/L) showed good linearity (r²≥0.9998). LOD and LOQ ranged from 0.15 to 0.31 mg/kg and from 0.44 to 0.93 mg/kg, respectively. The average accuracy and precision at 0.5, 2.5, and 10 mg/kg ranged from 84.3 to 102.0% and 0.7 to 3.0 relative standard deviation (RSD%), respectively. This study confirmed the applicability of the proposed method by applying it to commercial products, such as teas and beverages. Thus, the proposed analytical method is suitable for quantifying quercetin in various foods.

• Journal of Applied Biological Chemistry
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• 제64권3호
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• pp.285-290
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• 2021

Salicornia herbacea is a type of salt marsh plant that has been used in traditional medicine to treat several diseases. Isorhamnetin-3-O-glucoside (I3G) and quercetin-3-O-glucoside (Q3G) are major flavonoids in S. herbacea that are known to exert various pharmacological activities. Therefore, our study sought to validate and optimize an HPLC/UV-based analytical method for I3G and Q3G yield quantification, as well as to determine its limit of detection, limit of quantification, linearity, precision, and accuracy. Upon testing a concentration range of 31.5-1.9 ㎍/mL the results exhibited good linearity (r² ≥0.9996 and r² ≥0.9999 for I3G and Q3G, respectively), and the procedure was deemed precise (relative standard deviation of ≤3.19 and ≤3.85%, respectively), and accurate (102.6-105.0 and 92.9-95.2%, respectively). The results showed that our proposed method could be used for rapid I3G and Q3G evaluation in S. herbacea.

• Journal of Microbiology and Biotechnology
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• 제32권8호
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• pp.976-981
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• 2022

Phenanthrenes are bioactive phenolic compounds found in genus Dioscorea, in which they are distributed more in peel than in flesh. Recent studies on phenanthrenes from Dioscorea sp. peels have revealed the potential for valuable biomaterials. Herein, an analytical method using high-performance liquid chromatography (HPLC) for quantitation of bioactive phenanthrenes was developed and validated. The calibration curves were obtained using the phenanthrenes (1-3) previously isolated from Dioscorea batatas concentrations in the range of 0.625-20.00 ㎍/ml with a satisfactory coefficient of determination (R²) of 0.999. The limit of detection (LOD) and the limit of quantification (LOQ) values of the isolated phenanthrenes ranged from 0.78-0.89 and 2.38-2.71 ㎍/ml, respectively. The intraday and interday precision ranged from 0.25-7.58%. The recoveries of the isolated phenanthrenes were from 95 to 100% at concentrations of 1.25, 2.5, and 5.0 ㎍/ml. Additionally, phenanthrenes (1-3) were found in all investigated peel extracts. Hence, the developed method was encouraging for the quantitative analysis of phenanthrenes in genus Dioscorea.

• Nuclear Engineering and Technology
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• 제52권12호
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• pp.2852-2859
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• 2020

This paper deals with the simulation-based design optimization and experimental validation of the characteristics of an in-core silver Self-Powered Neutron Detector (SPND). Optimized dimensions of the SPND are determined by combining Monte Carlo simulations and analytical methods. As a first step, the Monte Carlo transport code MCNPX is used to follow the trajectory and fate of the neutrons emitted from an external source. This simulation is able to seamlessly integrate various phenomena, including neutron slowing-down and shielding effects. Then, the expected number of beta particles and their energy spectrum following a neutron capture reaction in the silver emitter are fetched from the TENDEL database using the JANIS software interface and integrated with the data from the first step to yield the origin and spectrum of the source electrons. Eventually, the MCNPX transport code is used for the Monte Carlo calculation of the ballistic current of beta particles in the various regions of the SPND. Then, the output current and the maximum insulator thickness to avoid breakdown are determined. The optimum design of the SPND is then manufactured and experimental tests are conducted. The calculated design parameters of this detector have been found in good agreement with the obtained experimental results.

• 한국식품영양학회지
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• 제35권6호
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• pp.543-551
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• 2022

There has been increased interest in lignans due to their potential effect in reducing the risk of developing several diseases. To evaluate lignan contents, sensitive and accurate methods should be developed for their quantification in food. The present study aimed to validate a liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for the quantification of 5 lignans: lariciresinol (Lar), matairesinol (Mat), pinoresinol (Pin), secoisolariciresinol (Seco), and syringaresinol (Syr). The validation included selectivity, linearity, recovery, accuracy, and precision. The method was proved to be specific, with a linear response (R²≥0.99). The limits of detection were 0.040~0.765 ㎍/100 g and the limits of quantification were 0.114~1.532 ㎍/100 g. Recoveries were 90.588~109.053% for black sesame powder. Relative standard deviations of repeatability and reproducibility were below 5%. Total lignan contents of roasted coffee bean, oat, and blacksoy bean were 105.702 ㎍/100 g, 78.965 ㎍/100 g, and 165.521 ㎍/100 g, respectively. These results showed that LC-MS/MS analysis would be effective in producing acceptable sensitivity, accuracy, and precision in five lignan analyses.

• 한국식품영양과학회지
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• 제43권11호
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• pp.1791-1795
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• 2014

본 연구에서는 HPLC를 사용하여 채소류 식품군에서 비타민 K1의 분석법을 확립하고 이에 대한 분석법 검증하고자 하였다. 그 결과 본 시험법에서 표준용액의 피크유지시간과 부추 추출액의 피크유지시간이 일치하여 특이성을 확인하였다. 검량선의 상관계수($R^2$)는 0.9994 이상으로 높은 유의수준을 보여 분석에 적합함을 알 수 있었으며, 검출한계는 0.1335 ng/injection volume($50{\mu}L$)이었고 정량한계는 0.2784 ng/injection volume($50{\mu}L$)으로 설정되었다. 일내, 일간분석에서 정밀도를 나타내는 변동계수(coefficient variation, CV)는 표준용액에서 각각 1.979%, 2.107%로 나타내었고 정확성은 99.439%로 나타내어 채소류에서 비타민 K1의 분석법이 적합한 시험법임이 검증되었다. 본 분석법에 따라 채소류의 비타민 K1을 분석한 결과 식품공전의 효소를 이용한 분석법보다 더 높은 추출률을 나타내었으며 다른 물질의 간섭 없이 분석 가능하여 채소류의 비타민 K1의 검출에 응용되어 이용될 수 있을 것으로 판단된다.

• 분석과학
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• 제24권6호
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• pp.544-555
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• 2011

본 연구는 농약류에 대하여 구조-활성의 정량적 관계(QSAR)를 이용하여 무지개 송어(학명: Oncorhynchus mykiss)의 급성 독성을 예측-분석하는 과정을 수행하였다. 모델 구현을 위해 사용된 275종의 농약류에 대한 수중 독성(96h $LC_{50}$) 값은 DEMETRA프로젝트의 데이터를 사용하였다. 예측 모델에 사용된 2차원 분자 표현자는 PreADMET프로그램으로부터 계산을 하였고, 선형 (다중 선형 회귀 방법)모델과 비선형(서포트 벡터 머신, 인공 신경망) 학습 방법들은 실험값과 예측값의 적합도를 고려하여 최적화 되었다. 데이터 전처리 과정을 거친 뒤에, 5묶음 교차 검증과정을 포함한 모집단 기반 전진 선택법을 통해서 각 학습 방법의 최적의 표현자 집합을 결정하였다. 가장 좋은 결과는 SVM 방법 ($R^2_{CV}$=0.677, RMSECV=0.887, MSECV=0.674) 이었고, EU의 규제 기준에 따른 분류에서는 87%의 정확도를 나타내었다. MLR방법을 통해서는 무지개 송어의 급성 독성에 대하여 독성을 나타내는 농약류의 구조적 특징과 지질 층과의 상호작용을 설명할 수 있었다. 개발된 모든 모델들은 5묶음 교차 검증과 Y-scrambling test을 통해 검증되었다.

• 고려인삼학회:학술대회논문집
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• 고려인삼학회 2002년도 학술대회지
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• pp.491-501
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• 2002

A cross-examination between KT&G Central Research Institute and Guangzhou Institute for Drug Control was carried out in order to select optimum conditions for extraction, separation and determination of ginsenosides in red ginseng and to propose a better method for the quantitative analysis of ginsenosides. The optimum extraction conditions of ginsenosides from red ginseng were as follows: the extraction solvent, $70\%$ methanol; the extraction temperature, $100^{\circ}C;$ the extraction time, 1 hour for once; and the repetition of extraction, twice. The optimum separation conditions of ginsenosides on the SepPak $C_{18}$ cartridge were as follows: the loaded amount, 0.4 g of methanol extract; the washing solvents, distilled water of 25 ml at first and then $30\%$ methanol of 25 ml; the elution solvent, $90\%$ methanol of 5 ml. The optimum HPLC conditions for the determination of ginsenosides were as follows: column, Lichrosorb $NH_2(25{\times}0.4cm,$ 5${\mu}m$, Merck Co.); mobile phase, a mixture of acetonitrile/water/isopropanol (80/5/15) and acetonitrile/water/isopropanol (80/20/15) with gradient system; and the detector, ELSD. On the basis of the optimum conditions a method for the quantitative analysis of ginsenosides were proposed and another cross-examination was carried out for the validation of the selected analytical method conditions. The coefficient of variances (CVs) on the contents of ginsenoside-$Rg_{1}$, -Re and $-Rb_1$ were lower than $3\%$ and the recovery rates of ginsenosides were $89.4\~95.7\%,$ which suggests that the above extraction and separation conditions may be reproducible and reasonable. For the selected HPLC/ELSD conditions, the CVs on the detector responses of ginsenoside-Rg, -Re and $-Rb_1$) were also lower than $3\%$, the regression coefficients for the calibration curves of ginsenosides were higher than 0.99 and two adjacent ginsenoside peaks were well separated, which suggests that the above HPLC/ELSD conditions may be good enough for the determination of ginsenosides.

• 한국작물학회지
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• 제49권3호
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• pp.211-215
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• 2004

미강에 함유되어 있는 토코페롤 및 토코트리에놀의 함량을 비파괴적으로 신속하게 추정하기 위하여 NIRS(근적외선 분광분석기)를 이용한 분석 방법을 검토하였다. 벼 유전자원 80계통의 미장을 사용하여 HPLC에서 분석된 토코페롤 및 토코트리에놀의 함량치를 NIRS 스펙트럼에 적용시킨 후 검량식을 작성하였다. NIRS의 검량식을 몇가지 방법에 의하여 비교 분석한 결과 2차 미분된 스펙트럼을 MPLS(Modified Partial Least Squares)를 이용한 회귀식에 이용하는 것이 가장 적합하였다. HPLC를 이용한 유전자원들의 성분 함량과 NIRS에서 도출된 검량식과의 상관계수는 토코페롤과 토코트리에놀이 각각 0.992, 0.953을 나타내었다. 이들 검량식은 validation file 에서도 0.846 및 0.956의 높은 상관을 보여 미강 상태에서 토코페롤 및 토코트리에놀의 함량을 NIRS를 이용하여 신속하게 분석할 수 있을 것으로 판단되었다.