• Proceedings of the Materials Research Society of Korea Conference
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• 2003.11a
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• pp.151-151
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• 2003

열화학기상증착법(Thermal-CVD)을 이용하여 SOI(snilicon-on-insulator)기판과 실리콘기판 상에 단결정 3C-SiC 이종박막을 동시에 성장하고, 그 특성을 비교 분석하였다. 결정성 평가로는 X-선 회절(XRD)분석과 Raman 산란 분광분석, 그리고 투과전자현미경을 이용하였고, 잔류 웅력 비교 분석으로는 laser scanning 방법 과 Raman 산란 분광분석의 3C-SiC LO peak의 위치변화, 그리고 X-선 회절분석의 3C-SiC(004) peak의 위치변화를 이용하였다. 그 결과 SOI 기판과 실리콘 기판상에 고품위의 단결정 3C-SiC 박막이 성장됨을 확인하였고, SOI 기판을 사용한 경우 실리콘 기판에 비해 성장된 3C-SiC 이종박막의 잔류 응력이 실제로 감소됨을 확인하였다.

• The Korean Journal of Pesticide Science
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• v.15 no.2
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• pp.160-165
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• 2011

Monitoring of pesticide residues were conducted at three sites in the Southern Area of Seoul, Korea (Gang-nam, Gang-dong and Song-pa). We measured pesticide residues within soil samples using multi-pesticide residues analysis. Samples were collected at the three sites with 60 sampling spots. The amount of pesticide residues in the soil samples were as follows [(minimum-maximum), mg/kg] endosulfan 0.002-0.999, procymidone 0.002-1.200, diazinon 0.003-0.024, metalaxyl 0.012-0.075. In soil treated with 0.445 mg/kg of endosulfan, the pesticide absorbed by chamnamul, was 0.157 mg/kg (Absorption rate : 35.3%). However, in soil treated with 0.358 mg/kg of endosulfan, the pesticide absorbed by lettuce, was 0.004 mg/kg (Absorption rate : 1.1%).

• Analytical Science and Technology
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• v.10 no.3
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• pp.168-178
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• 1997

The optimum conditions for the residual analysis of the ethalfluralin herbicide on soils were investigated and the residues in soils were determined by gas chromatography with electron capture detector(GC-ECD). The soil samples extracted with methanol and dichloromethane and concentrated. The concentrated phase were redissolved with toluene and analyzed with GC-ECD after separated by cyanosilica gel Sep-Pak cartridge. From the standard addition experiments with 0.1 and 1.0ppm, the average recoveries were 92.8~101.2% and the detection limit was 0.004ppm. The half-life time of ethalfluralin in the soil(A) was 35 days in the laboratory and 7.2 days in the field test whereas it was 45 days and 9.7 days for each in case of soil(B).

• Analytical Science and Technology
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• v.26 no.2
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• pp.154-163
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• 2013

The maximum residue limits of pyrimisulfan is set as 0.05 mg/kg in rice in 2011, so very reliable and sensitive analytical method for pyrimisulfan residues is required for ensuring the food safety of pyrimisulfan residues in agricultural products. In this study, a rapid and sensitive analytical method was developed and validated using liquid chromatography electrospray ionization tandem mass spectrometry (LC-MS/MS) for the determination of herbicide pyrimisulfan residues in agricultural products. Average recoveries of pyrimisulfan ranged from 88.7 to 99.3% at the spiked level of 0.005 mg/kg and from 90.1 to 94.2% at the spiked level of 0.05 mg/kg, while the relative standard deviation was less than 10%. Linear range of pyrimisulfan was between 0.01~1.0 ${\mu}g/mL$ with the correlation coefficient ($r^2$) 0.999 and limit of quantification was 0.005 mg/kg. The results of method validation were satisfied Codex guideline. The results revealed that the developed and validated analytical method is possible for pyrimisulfan determination in agricultural product samples and will be used as an official analytical method.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 1997.04a
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• pp.181-187
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• 1997

고강도 알루미늄 합금 링롤재의 급냉, 링 팽창(expansion) 및 링 압축(compression) 응력제거처리후 잔류응력을 예측하기 위하여 2차원 축대칭 열해석 및 탄소성 해석을 수행하였다. 급냉 및 응력제거처리 후 2단 과시효 처리(T73)된 링롤재에 대하여 3단계 절단법(Three step sectioning method)을 적용하여 링롤재의 두께에 따른 잔류응력 분포를 측정하였으며, 측정결과를 급냉 및 응력제거처리후 잔류응력 해석결과와 비교분석하였다. 링의 급냉후 원주 및 축방향의 잔류응력 해석값은 T73후 측정값과 비슷한 경향을 보였으며, 링의 내면과 외면에서 압축응력을 나타내었고 중심에서 인장응력을 나타내었다. 잔류응력은 링 팽창(T7351) 및 링 압축(T7352) 적용후 T73에 비해 현저히 감소하였으며, 축방향의 제거 효과가 원주방향보다 우수하게 나타났다. 또한 링 압축에 의한 제거효과가 링 팽창보다 크게 나타났다. 링롤재의 응력제거처리는 제거 효과 및 실용성 측면에서 링 압축 공정이 유리하며, 치수제어 및 장비용량 측면에서 링 팽창 공정이 유리하다는 결론을 얻었다.

• The Korean Journal of Pesticide Science
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• v.16 no.4
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• pp.308-314
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• 2012

In order to monitor the residual pesticides in environment friendly agricultural commodities, fruits and fruiting vegetables. Twenty-five agricultural commodities were collected twice in May and August 2011 from nine environment friendly agricultural commodities-selling supermarkets and retail stores located in eight major cities in Korea. The number of each agricultural commodity collected, 555 samples in total, was 152 organic agricultural products, 202 pesticide-free agricultural products and 201 low-pesticide agricultural products. Pesticide residues in samples were analyzed by multiresidue method for 245 pesticides using a GC-ECD/NPD and an HPLC-DAD/FLD and the peaks suspected as pesticides were identified with a GC/MSD. As a result of pesticide residue analysis, three pesticides, bifenthrin, EPN and chlorpyrifos, were detected from four samples including apple, representing a detection rate of 0.72%. The residue levels of the four pesticide-detected samples were less than their maximum residue limits (MRLs) but one pesticide EPN detected from pear exceeded its legible criterion of one twentieth MRL. Estimated daily intakes of the pesticides detected from fruits and fruiting vegetables were less than 0.76% of their maximum permissible intake.

• Journal of Food Hygiene and Safety
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• v.37 no.4
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• pp.238-248
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• 2022

This study was conducted to evaluate the safety of 208 types of residue pesticides on 150 dried agricultural products in Ulsan. The pesticide residues were detected using GC-MS/MS, LC-MS/MS, GC/ECD, GC/NPD, and LC/PDA. The detection rate was 19.3% (29 of 150 samples), and 28 types of pesticides were detected. Two of the 29 pesticide residues exceeded the maximum residue limit (MRL). Difenoconazole was detected in Ulleungdo aster, and chlorothalonil and chlorpyrifos were detected in chili pepper leaves. In the vegetable group, the frequency of pesticide residues was found to be the highest in dried leafy vegetables, followed by dried fruiting vegetables other than cucurbit vegetables, and then dried stalk and stem vegetables. The pesticide types detected in the commercial dried agricultural products were fungicide (60%), insecticide (23.8%), and acaricide (16.3%). In the validation study, the values of limit of detection (LOD), limit of quantitation (LOQ), coefficient of determination (R²), and recovery rate were in the range of 0.0001-0.0409 mg/kg, 0.0003-0.1241 mg/kg, 0.994-0.999, and 81.58-116.79%, respectively. The ratio of estimated daily intake (EDI)/acceptable daily intake (ADI) was 0.00002-0.31395%.

• Journal of the Korean Recycled Construction Resources Institute
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• v.11 no.4
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• pp.391-399
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• 2023

Recently, low-temperature pyrolysis technology has been studied as a recycling method for waste plastic. Low-temperature pyrolysis technology for waste plastic produces pyrolysis oil that can be used as an energy resource, but solid residue remains. Waste plastic pyrolysis residues are mostly landfilled due to their limited use. In this study, it is investigated that mixed waste plastic pyrolysis residues could be recycled into activated carbon. It was confirmed that the fixed carbon content of the residue was 33.69 % from proximate Analysis. Chemical activation was used to manufacture activated carbon. KOH was used as an activator. To investigate the effect of the mixing ratio of KOH and residue, samples were mixed at ratios of 0.5, 1.0, and 2.0. The mixed sample was chemically activated at an activation temperature of 800 ℃ for 1 hour. As a result of analyzing the characteristics of activated carbon through BET, it was confirmed that the specific surface area increased as the mixing ratio of KOH increased.

• Journal of Korean Ophthalmic Optics Society
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• v.13 no.4
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• pp.155-160
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• 2008

Purpose: To develop a program for analyzing the condition of implanted ICL lenses in case the residual astigmatism appears after the implantation. Methods: From analyzing the measured residual astigmatism after operating ICL lens, we could induce formulas that produce the rotating angle and the corresponding MR prescription of the implanted ICL lens. Using the Delphi 6.0 language, we could develop a program by which we conveniently confirm, in the window screen visually, the rotating angle and the corresponding MR prescription of the implanted ICL lens calculated by these formulas. Results: We induced formulas that produce the rotating angle and the corresponding MR prescription of the implanted ICL lens by analyzing the measured residual astigmatism after operating ICL lens and developed a program which can analyze the condition of the implanted ICL lens. By this program we could easily analyze the condition of the implanted ICL lens. Conclusions: Judging from the results of applying this program to many clinical cases, we could conclude that this program is very effective in analyzing the condition of implanted ICL lenses.

• The Korean Journal of Pesticide Science
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• v.20 no.1
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• pp.23-29
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• 2016

This study was carried out to survey residual characteristics of pesticide in fresh ginsengs collected from 45 markets at 15 regions in Korea using multiresidue analysis with a GC-MS/MS and an LC-MS/MS. After residue analysis was performed, the pesticides detected from ginsengs were quantitated using their analytical methods validated by recovery tests with a GC-ECD/NPD. As a results of analysis of pesticide residue, cypermethrin, fenitrothion, fludioxonil, thifluzamide, and tolclofos-methyl were detected from 16 samples among 45 samples in total, indicating detection rate was 35.6%. Tolclofos-methyl was found to be highest in detection frequency in ginseng. Fenitrothion that has not established maximum residue limit and pre-harvest interval for ginseng was detected. The amounts of all pesticides detected were less than their MRLs. Ratios of estimated daily intakes to acceptable daily intakes of the detected pesticides in ginseng were found to be from 0.03 to 16.67%.