• 농약과학회지
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• 제16권4호
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• pp.350-356
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• 2012

숙련도시험 수행 및 분석법확립은 분석기관의 지속적인 시험결과에 대한 신뢰성 확보 및 시험기관의 분석능력 관리를 위한 정도관리 체계에 포함되는 항목이다. Emamectin benzoate 및 lufenuron 유제 시료에 대한 분석법 검증, 안정성 및 균질성을 확인한 후, 농약 이화학시험 분석기관(33개 기관)을 대상으로 두 약제에 대한 시료를 배포하여 숙련도시험을 수행하였으며, 분석기관의 수행능력을 z값으로 평가하였다. Emamectin benzoate는 참여기관 총 33개 중 이상값은 2개 기관(6.0%), z값이 |Z| > 3.0 및 |Z| < -3.0 범위을 나타내는 부적합은 2개 기관(6.0%) 및 z값이 -2.0 < |Z| -3.0 및 2.0 < |Z| < 3.0 범위인 검토대상은 3기관(9.0%)이었고, lufenuron에 대한 z값의 범위가 검토대상인 기관은 3개(9.0%)였다. 본 연구는 국내 농약 이화학시험 분석기관에 적합한 정도관리 체계 마련을 위하여 숙련도 시험의 적용가능성을 확인하였으며, 추가적으로 다양한 농약제품에 대한 숙련도시험을 수행하여 보완이 필요하다.

• 한국환경농학회지
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• 제39권2호
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• pp.130-137
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• 2020

BACKGROUND: Mefentrifluconazole and triticonazole are the triazole fungicides. The maximum residue levels for agricultural products need to be set up. Therefore, development of the official analytical method for determination of mefentrifluconazole and triticonazole residues from agricultural crops was necessary due to safety management, and then a simultaneous analytical method was developed for the determination of mefentrifluconazole and triticonazole in agricultural crops. METHODS AND RESULTS: Samples were extracted using acetonitrile and purified using dispersive solid phase extraction, and then detected with liquid chromatograph-tandem mass spectrometry (LC-MS/MS). Matrix-matched calibration curves (0.0025-0.25 ㎍/mL) were linear into a sample extract with r²>0.99. For validation, the recovery test was carried out at three fortification levels (LOQ, 10 LOQ and 50 LOQ) from agricultural samples. The results for mefentrifluconazole and triticonazole ranged between 92.3 to 115.3% and 91.4 to 108.5%, respectively and RSD (relative standard deviation) values were also below 6.0%. Furthermore, inter-laboratory was conducted to validate the method. CONCLUSION: All values were corresponded with the criteria ranges requested by both the CODEX (CAC/GL 40-1993, 2003) and MFDS guidelines (2016). Therefore, the proposed method can be used as an official analytical method for determination of mefentrifluconazole and triticonazole (triazole fungicides) in the Republic of Korea.

• 한국식품영양과학회지
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• 제40권4호
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• pp.565-569
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• 2011

개별인정형 건강기능식품 기능성 원료로 개발한 창녕양파추출액의 표준화를 위해 지표성분으로 quercetin을 설정하였으며, HPLC를 이용하여 지표성분 quercetin의 분석법을 확립하며 그에 따른 유효성 검정을 실시하고자 하였다. 유효성 검정 결과, 본 시험법에서 표준용액의 피크유지시간과 창녕양파추출액의 피크유지시간이 일치하였으며 동일한 spectrum을 나타내어 특이성을 확인하였다. 검량선의 상관계수($R^2$)는 0.9986로 높은 직선성을 보여 분석에 적합함을 알 수 있었으며, 검출한계는 0.2 mg/L, 정량한계는 0.5 mg/L 로 설정되었다. Quercetin의 회수율은 0.05 mg/mL에서는 82.36~95.26%, 0.075 mg/mL는 82.70~98.24%, 0.1 mg/mL은 87.91~95.11%의 범위의 회수율을 보였으며, intra-day에서의 정밀도(RSD)는 0.10~3.28%, inter-day에서는 0.96~5.79%의 정밀도를 나타내어 창녕양파추출액의 지표성분인 quercetin의 분석법은 적합한 시험법임이 검증되었다.

• 한국환경농학회지
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• 제41권2호
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• pp.135-151
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• 2022

BACKGROUND: The β-agonists known as phenyl ethanolamine derivatives have a conjugated aromatic ring with amino group. They are used as tocolytic agents and bronchodilator to human and animal generally, and some of them are used as growth promoters to livestock. METHODS AND RESULTS: β-agonists in samples were extracted by 0.4 N perchloric acid and ethyl acetate. The target compounds were analyzed by liquid chromatography-electrospray tandem mass spectrometry (LC-ESI-MS/MS). Validation of method was performed according to CODEX guidelines (CAC/GL-71). The matrix matched calibration gave correlation coefficients>0.98, and the obtained recoveries were in the range of 62.0-109.8%, with relative standard deviation ≤ 20.1%. In addition, a survey was performed to inspect any residual β-agonist from 100 samples of livestock and fishery products and ractopamine was detected in one of the 100 samples. CONCLUSION(S): In this study, we established the analytical method for β-agonists through using the expanded target compounds and samples. And we anticipate that the established method would be used for analysis to determine veterinary drug residues in livestock and fishery products.

• Journal of Ginseng Research
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• 제37권4호
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• pp.475-482
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• 2013

The main active components of Panax ginseng are ginsenosides. Ginsenoside Rb1 and Rg1 are accepted as marker substances for quality control worldwide. The analytical methods currently used to detect these two compounds unfairly penalize steamed and dried (red) P. ginseng preparations, because it has a lower content of those ginsenosides than white ginseng. To manufacture red ginseng products from fresh ginseng, the ginseng roots are exposed to high temperatures for many hours. This heating process converts the naturally occurring ginsenoside Rb1 and Rg1 into artifact ginsenosides such as ginsenoside Rg3, Rg5, Rh1, and Rh2, among others. This study highlights the absurdity of the current analytical practice by investigating the time-dependent changes in the crude saponin and the major natural and artifact ginsenosides contents during simmering. The results lead us to recommend (20S)- and (20R)-ginsenoside Rg3 as new reference materials to complement the current P. ginseng preparation reference materials ginsenoside Rb1 and Rg1. An attempt has also been made to establish validated qualitative and quantitative analytical procedures for these four compounds that meet International Conference of Harmonization (ICH) guidelines for specificity, linearity, range, accuracy, precision, detection limit, quantitation limit, robustness and system suitability. Based on these results, we suggest a validated analytical procedure which conforms to ICH guidelines and equally values the contents of ginsenosides in white and red ginseng preparations.

• Structural Engineering and Mechanics
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• 제9권4호
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• pp.323-338
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• 2000

An analytical approach for the prediction of the behaviour of steel-fiber reinforced concrete beams subjected to torsion is described. The analysis method employs a special stress-strain model with a non-linear post cracking branch for the material behaviour in tension. Predictions of this model for the behaviour of steel-fiber concrete in direct tension are also presented and compared with results from tests conducted for this reason. Further in this work, the validation of the proposed torsional analysis by providing comparisons between experimental curves and analytical predictions, is attempted. For this purpose a series of 10 steel-fiber concrete beams with various cross-sections and steel-fiber volume fractions tested in pure torsion, are reported here. Furthermore, experimental information compiled from works around the world are also used in an attempt to establish the validity of the described approach based on test results of a broad range of studies. From these comparisons it is demonstrated that the proposed analysis describes well the behaviour of steel-fiber concrete in pure torsion even in the case of elements with non-rectangular cross-sections.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2014년도 춘계학술대회 논문집
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• pp.233-237
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• 2014

In this paper, the finite element modeling of the RK4 rotor kit system (RK4) and then frequency analysis and transient analysis, and was compared with the actual experimental results. RK4 manufactured by General Electric for the purpose of education and research. It is composed of two shaft, Two shaft is connected using a flexible coupling, one disk is mounted. The analytical model is modeled by using the ANSYS finite element analysis program commercially available. Based on impact hammer test results, material properties and the stiffness of the bearing and coupling was tuned. Considering the operating conditions and the vibration response of the analytical model were compared with experimental results.

• Structural Engineering and Mechanics
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• 제13권1호
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• pp.103-116
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• 2002

A solution based on the linear three-dimensional theory of elasticity is developed for vibration and elastostatic problems of hollow toroids. The theory is developed for transversely isotropic toroids of arbitrary thickness, and has the potential to validate some vehicle and aircraft tire models in the linear range. In the semi-analytical method that is adopted Fourier series are written in the circumferential direction, forming a set of two-dimensional problems. These problems are solved using the differential quadrature method. A commercial finite element program is used to determine alternative solutions. For validation both problems of vibration and elastostatics are considered. Finally results are determined for local surface loading problems, and conclusions are drawn.

• Tribology and Lubricants
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• 제11권5호
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• pp.93-98
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• 1995

To increase the information storage density in magnetic disk files, the head, the headdisk spacing must be reduced. This has motivated the investigation of alternatives to the conventional air-lubricated head-disk interface (HDI), which operates at a spacing of about 100 nm. One such alternative under consideration is the liquid-lubricated bearing. To properly model the HDI with a liquid bearing it is necessary to incorporate the theological properties of liquid lubricants at high shear rates. These rheological properties themselves are most easily measured within the HDI. Recently, some question has arisen in the literature concerning the interpretation of the frictional data acquired in this manner. In this study analytical and numerical solutions of the Reynolds eqn. are applied to the starved, liquid lubricated HDI to provide some validation of the rheological data reported the author and coworkers (Streator et al., 1994). Results of the analysis highlight the importance of the inlet taper region in determining the equilibrium configuration of the starved HDI even when only a small fraction of its length is wetted by the lubricant.

• Food Science and Biotechnology
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• 제18권6호
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• pp.1515-1518
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• 2009

The objective of this study was to compare 3 extraction methods including, solid phase extraction (SPE), acetonitrile extraction, and methanol extraction, for their usefulness as extraction methods to determine capsaicinoids. The determination of capsaicinoids in the extracts was carried out on a reverse-phased high performance liquid chromatography (HPLC) using a fluorescence detector. Three extraction methods, i.e., SPE, acetonitrile extraction, and methanol extraction were compared for the quantification of capsaicinoids using raw peppers and pepper powder. The highest analytical values were observed using methanol extraction and the lowest values using SPE. Also, the analytical method validation parameters such as accuracy, precision, limit of detection, limit of quantitation, and specificity were calculated to ensure the method's validity. This method provides a fast and accurate approach for the determination of capsaicinoids in peppers.