• Journal of the Korean Society of Radiology
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• v.15 no.6
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• pp.781-788
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• 2021

Due to the high sensitivity to radiation, excessive exposure needs to be prevented by accurately measuring the dose irradiated to the skin during radiation therapy. Although clinical trials use dosimeters such as film, OSLD, TLD, glass dosimeter, etc. to measure skin dose, these dosimeters have difficulty in accurate dosimetry on skin curves. In this study, to solve these problems, we developed a skin dosimeter that can be attached according to human flexion and evaluated its response characteristics. For the manufacture of the dosimeter, lead oxide (PbO) with high atomic number (Z_Pb: 82, Z_O: 8) and density (9.53 g/cm³) and silicon binders that can bend according to human flexion were used. In the case of a dosimeter made of PbO material, the performance degradation has been prevented by using parylene and others due to the presence of degradation due to oxidation, but the previously used parylene is affected by bending, so a new form of passive layer was produced and applied to the skin dosimeter. The characteristic evaluation of the skin dosimeter was evaluated by analyzing SEM, reproducibility, and linearity. Through SEM analysis, bending was evaluated, reproducibility and linearity at 6 MeV energy were evaluated, and applicability was assessed with a skin dosimeter. As a result of observing the dosimeter surface through SEM analysis, the parylene passive layer PbO dosimeter with the positive layer raised to the parylene produced cracks on the surface when bent. On the other hand, no crack was observed in the silicon passive layer PbO dosimeter, which was raised to silicon passive layer. In the reproducibility measurement results, the RSD of the silicon passive layer PbO dosimeter was 1.47% which satisfied the evaluation criteria RSD 1.5% and the linearity evaluation results showed the R² value of 0.9990, which satisfied the evaluation criteria R² 9990. The silicon passive layer PbO dosimeter was evaluated to be applicable to skin dosimeters by demonstrating high signal stability, precision, and accuracy in reproducibility and linearity, without cracking due to bending.

• Journal of Food Hygiene and Safety
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• v.34 no.2
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• pp.148-157
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• 2019

An optimized analytical method for sodium iron chloriphyllin in foods was established and verified by using high performance liquid chromatography with attached diode array detection. An Inertsil ODS-2 column and methanol-water (80:20 containing 1% acetate) as a mobile phase were employed. The limit of detection and quantitation of sodium iron chloriphyllin were 0.1 and 0.3 mg/kg, respectively, and the linearity of calibration curve was excellent ($R^2=0.9999$). The accuracy and precision were 93.9~104.95% and 2.0~7.7% in both inter-day and intra-day tests. Recoveries for candy and salad dressing were ranged between 93 and 104% (relative standard deviation, (RSD) 0.3~4.3%), and between 83 and 115% (RSD 1.2~2.0%), respectively. Liquid chromatography mass spectrometry was used to verify the main components of sodium iron chlorophyllin which were Fe-isochlorin e4 and Fe-chlorin e4.

• Korean Journal of Food Science and Technology
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• v.52 no.6
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• pp.565-572
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• 2020

The 3-monochloropropane-1,2-diol (3-MCPD) is a contaminant that occurs in foodstuffs in its free form as well as in its bound form. The objective of this study was to evaluate the effects of emulsifier, frying temperature, and the amounts of salt and oil on the formation of bound 3-MCPD in a fried snack model. Emulsifier affected the formation of bound 3-MCPD; furthermore, it was observed that the largest amount of bound 3-MCPD was detected in the fried snack model when glycerin esters of fatty acids were used as emulsifiers. Frying temperature also affected the formation of bound 3-MCPD, which increased significantly as the frying temperature increased from 145 to 190℃. In addition, salt affected the formation of bound 3-MCPD. As the amount of salt increased, the amount of bound 3-MCPD also increased significantly. Moreover, it was observed that the amount of oil did not affect the formation of bound 3-MCPD. These results will aid in the reduction of bound 3-MCPD in fried snacks.

• Journal of the Korean Society of Radiology
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• v.17 no.3
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• pp.433-440
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• 2023

High dose rate brachytherapy is a cancer treatment that intensively irradiates radiation to tumors by inserting isotopes with high dose rates into the body. For such a treatment, it is necessary to deliver an accurate dose to the tumor tissue through an accurate treatment plan while delivering only a minimum dose to the normal tissue. Therefore, it is very important to check the location accuracy of the source through accurate Quality Assurance (QA) in clinical practice. However, since the source position is determined using a ruler, automatic radiographer, video monitor, etc. in clinical practice, it yields inaccurate results. In this study, a semiconductor dosimeter using CsPbI₂Br and CsPbIBr₂ was fabricated. And, in order to analyze whether it is more suitable for the relative QA dosimeter for brachytherapy device among the two materials, the radiation detection ability of each was compared and evaluated. In order to evaluate the radiation detection ability in brachytherapy, the reproducibility and linearity of the two materials were evaluated in ¹⁹²IR. In the reproducibility evaluation, CsPbI₂Br presented a Relative Standard Deviatio(RSD) of 0.98% and CsPbIBr₂ presented an RSD of 3.45%. In the linearity evaluation, the coefficient of determination (R²) of CsPbI₂Br was presented as 0.9998, and the R² of CsPbIBr₂ was presented as 0.9994. As a result of the evaluation, it was found that CsPbI₂Br was more stable in radiation detection while satisfying the evaluation criteria in the dosimeter manufactured in this experiment. Therefore, CsPbI₂Br material is suitable for application as a relative dosimeter for radiation detection in brachytherapy devices.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.10 no.6
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• pp.2606-2626
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• 2016

This article investigates the distributed data storage problem in the space information network (SIN) using distributed fountain codes. Since space nodes in the SIN are resource-limited, in order to reduce energy consumption while improving the storage reliability, an efficient distributed storage based on fountain codes and probabilistic broadcasting (DSFPB) strategy is proposed. In the proposed strategy, source packets are disseminated among the entire network according to probabilistic broadcasting (PBcast), and the final degree distribution is close to the desired robust soliton distribution (RSD), this is benefited from the appropriate packets encoding procedure of the proposed strategy. As presented by the analysis and simulations, the total cost of data dissemination is greatly reduced compared with existing representative strategies, while improving the decoding performance.

• YAKHAK HOEJI
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• v.42 no.3
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• pp.243-247
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• 1998

A method for the determination of basic drugs based on their reaction with picric acid to form an ion-association complex extractable into several plasticizers was developed. Ba sic drugs-picric acid complexes in acid medium could be extracted quantitatively into several plasticizers except phosphates. For example, the chlorpromazine-picric acid complex showed maximum absorbance at near 410nm and was applied to extraction spectrophotometric determination of chlorpromazine. The calibration curves are linear (r>0.998) within a range from $10^{-6}to\;5{\times}10^{-4}M$ and the precision of the method was acceptable because RSD was less than 2.6% (n=7). The factors affecting the extraction system was discussed.

• Proceedings of the Safety Management and Science Conference
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• 2006.04a
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• pp.411-419
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• 2006

This paper aims at designing an accelerated life test sampling plan for bulk material and showing its application for an arc-welded gas pipe. It is an integrated model of the accelerated life test procedure and bulk sampling procedure. The accelerated life tests were performed by the regulation, RSD 0005 of ATS at KITECH and bulk sampling was used for acceptance. Design parameters might be total sample size(segments and increments), stress level and so on. We focus on deciding the sample size by minimizing the asymptotic variance of test statistic as well as satisfying consumer's risk under Weibull life time distribution with primary information on shape parameter.

• Journal of Korean Society for Atmospheric Environment
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• v.7 no.2
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• pp.137-142
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• 1991

A method is developed for the simultaneous determination of dissolved iron, copper, and zinc in rainwater. The method involves 25-fold evaporative concentration, ion chromatographic separation and subsequent spectrophotometric detection after post-column reaction with 4-(2-pyridylazo) resorcinol. Analytical sensitivities, being defined by the slopes of calibration curves, are 0.93, 0.54, and 0.11 Abs/ $\mu$g/ml for iron, copper, zinc, respectively. Detection limits render around a few tenth of one ng/ml. Precisions evaluated by replicate analysis of real sample are better than 10% RSD. Due to the lack of certified standards for rainwater, the accuracy of the method could not be assessed directly. However, the results of this method agree well with those by inductively coupled plasma mass spectrometry. Analytical results for a suite of Seoul rainwaters are presented herein.

• 한국정보통신설비학회:학술대회논문집
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• 2002.08a
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• pp.27-30
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• 2002

10-bit 해상도, 10MS/s의 ADC를 Stage 당 1.5-Bit의 Resolution을 가지는 Redundant signed digit(RSD) 방식의 파이프라인 구조를 이용하여 설계하였다. Error Correction Logic을 사용함으로써 비교기를 Coarse하게 설계하였고 잔류 전압 증폭기의 최적 Scaling을 통하여 일반적인 ADC에 비해 성능 저하 없이 효율적으로 소비 전력을 감소시켰다. 또한, Charge Pump의 선택적 사용을 통해 기생 커패시턴스의 영향을 최소화함으로써 잔류전압 증폭기의 출력 전압 특성을 향상 시켰다. 삼성 0.35u CMOS 공정 파라미터를 이용하여 입력 전압 $-1{\sim}1V$, 공급 전압 $-1.5{\sim}1.5V$에서 18.73mW로 설계하였으며 HSPICE로 시뮬레이션 하였다.

• Bulletin of the Korean Chemical Society
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• v.29 no.1
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• pp.99-103
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• 2008

Solvent extraction using salphen as a ligand has been investigated for the selective separation and determination of trace Fe(II) and Fe(III). A salphen ligand was synthesized, and solvent extraction variables, such as solution pH, the concentration of salphen, the type of organic solvent, auxiliary agents, oxidants and the effect of interference were optimized. Salphen is stable at pH 3-4, and Fe(III)-salphen complexes can be selectively extracted into an MIBK(4-methyl-2-pentanone) phase from an aqueous solution within this pH range. For the determination of the total amount of iron in 100 mL of aqueous solution, Fe(II) ions were completely oxidized using 0.05 mL of 3.5% H2O2 without side reactions. To evaluate its applicability, the proposed method was applied to determine trace Fe(II) and Fe(III) in several kinds of water samples. Reproducible results were obtained with RSD of less than 3.0%, and the recoveries for this reliability were obtained with 91-112%.