• Proceedings of the Korea Air Pollution Research Association Conference
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• 2003.11a
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• pp.491-492
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• 2003

최근 국제적으로는 2005년 대기배출허용기준 강화와 총량규제 도입추진, 대기 배출부과금 제도의 강화 움직임, 대기환경규제지역의 규제지역 확대에 따른 굴뚝자동측정기 부착의무화, VOCs(휘발성유기화합물) 물질 배출원 관리가 강화되는등 환경적 이슈가 점점 높아지고 있는 추세이다. 또 외부적으로 기후변화협약에 따른 온실가스 규제와 스톡홀름협약에 따른 POPs물질(잔류성유기오염물질)규제가 예상되며 이에 따라 국내 환경부에서도 05년까지 오염물질 배출농도 강화와 POPs 물질 inventory 구축작업과 소각로 이외의 다이옥신 배출원에 대한 다이옥신규제 대상시설이 확대될 전망이다. (중략)

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2009.05a
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• pp.192-193
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• 2009

CrN 코팅막은 고온에서 치밀한 Cr2O3 확산방지막을 형성함으로 $800^{\circ}C$까지 기계적성질을 유지할 수 있다. 본 실험에서는 Ar, N2, 그리고 $O_2$ 가스 분위기에서 AIP(Arc Ion Plating) 기법에 의해 다양한 조성의 Cr-O-N 박막을 Si(200)과 AISI 304 기판 위에 증착되었다. Cr-O-N 코팅막은 47.4at% 미만의 산소함량을 포함 할 때까지 B1구조를 유지하였고 코팅막 내 산소함량 24.6at%에서는 강한 XRD peak intensification을 나타내었다. 47.4at%에서는 결정상을 전혀 찾아볼 수 없는 전이구조를 나타내었고, 그 이상의 산소함량에서는 Cr22O3 결정상을 나타내었다. Cr-O(17at%)-N 조성의 코팅막에서는 (200)배향의 Grain 크기 증가 및 압축잔류응력이 증가하였으나, 그 이상의 산소함량에서는 점차 감소하였다. Cr-O(24.6at%)-N 조성의 코팅막이 가장 높은 경도를 나타내었고, 산소함량이 증가할수록 점차 향상된 마찰특성을 보였다.

• Proceedings of the Korea Society of Environmental Toocicology Conference
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• 2002.10a
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• pp.153-153
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• 2002

수돗물의 염소소독 과정에서 부식질의 초기 분해생성물인 MX(Mutagen X)는 수돗물의 전체 돌연변이유발성의 최고 60%까지 차지하는 것으로 알려져 있다. 그러나 존재하는 농도는 수 ng/L로 정량분석을 위해서는 resin을 사용하여 10 ~ 20L의 물을 농축하여야 한다. 이 연구에서 MX의 농축에 사용된 resin은 XAD-4와 XAD-7HP의 1:1 mixture이었으며, 사용 전에 Soxhlet extractor를 사용하여 ethyl acetate와 methanol로 각각 12시간씩 세척하였다. 15L의 물 시료는 37%의 염산으로 pH 2에 맞춘 후 직경 2cm의 유리관에 15cm의 높이로 채워진 resin을 40mL/min의 유속으로 통과시켰다. 유리관에 잔류하는 물은 질소가스로 대부분 불어 제거한 후 ethyl acetate 200mL를 가해 1mL/min의 유속으로 흘려주어 MX를 용출시킨 후 회전증발기로 5mL의 부피까지 농축시키고 10% H$_2$SO$_4$ in MeOH 0.1mL를 가하여 6$0^{\circ}C$에서 methyl ester화하였다. 과포화된 $Na_2$SO$_4$ 수용액 0.3ml를 가한 후 MTBE 0.3mL로 추출하고 GC/ECD로 분석하였다. MX의 회수율은 60% 이상이었으며 일부수돗물 시료에 대해 분석하였다.

• Proceedings of the KSME Conference
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• 2001.06a
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• pp.339-344
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• 2001

The transmission pipeline industry spends many millions of dollars annually performing inline inspections, excavating sites of possible corrosion, and repairing or replacing damaged sections of pipe. New criteria for evaluation the integrity of corroded pipe have been developed in recent years to help in controlling these costs. These new criteria vary widely in their estimates of integrity and the most appropriate criterion for a given pipeline is not always clear. This paper presents an overview, comparison and evaluation of acceptability criteria for corrosion defects in pipelines. By full scale burst tests, this paper have assessed the relative accuracy of each of theses criteria in predicting failure and remaining strength. Many of the criteria appear to be excessively conservative and indicate that defects must be repaired when none is needed, based upon burst test data.

• Proceedings of the KSME Conference
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• 2008.11b
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• pp.3032-3037
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• 2008

Variable Valve Timing (VVT) system can be used to improve fuel economy, performance and emissions. This study is identified the effect of VVT in terms of wide open throttle torque, Residual gas fraction, volume efficiency. Engine cycle simulations are performed on 2.0L DOHC in-line 4-cylinder SI engine by using WAVE of Ricardo. Results of the simulations had good agreement with WOT torque experimental data, and helped to predict the tendency of performance as the valve timings change. WOT torque was higher when intake valves were closed early for low rpm and late for high rpm.

• YAKHAK HOEJI
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• v.45 no.5
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• pp.437-441
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• 2001

The quasi-drugs including nonwoven fabric and gauze were sterilized using ethylene oxide (EO) gas. Residual EO in the quasi-drugs was extracted with water (20 mL of water for 1 g of sample) for 24h at 37$^{\circ}C$. Residual EO was determined using GC. The optimal analytical conditions were as follows : column, Carbowax 20M (1.D. 0.2 mm); mobile phase, helium with 30 mL/min; oven temperature 57$^{\circ}C$, injector temperature 18$0^{\circ}C$, detector temperature 20$0^{\circ}C$. The detection limit for EO was 0.10$\mu$g/mL. When the residual EO extracted from nonwoven fabric and gauze was determined, it took more than 9h to get the lower level than 25 ppm which is the limit value of FDA guideline. When the EO residues, ethylene chlorohydrine (ECH) and ethylene glycol (EG) in the 7 commercially available quasi-drugs were determined, no residual EO, ECH, EG were found from the seven commercially available quasi-drugs analyzed by this method.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2008.11a
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• pp.81-82
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• 2008

하이브리드 코팅 시스템을 이용하여 $CrMoC_xN_{1-x}$ 박막을 AISI D2와 실리콘 웨이퍼 모재 위에 증착하였다. 박막 내 탄소 함량은 $CH_4/(CH_4+N_2)$ 가스 유량 증가에 비례하여 증가했다. 탄소 함량이 0.33일 때 44GPa의 최대강도 및 -4.4GPa의 잔류응력을 나타내었다. CrMoN 박막의 평균 마찰계수는 0.42이지만, 탄소함량을 증가함에 따라 0.31까지 감소 하였다. 이것은 박막 표면과 스틸볼 사이에서 탄소가 풍부한 층이 형성되어 일종의 고체윤활제 역할을 했기때문이다. 박막의 미세조직은 X-ray diffraction, Scanning electron microscopy, 그리고 X-ray photoelectron spectroscopy를 이용하여 분석하였다.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2007.11a
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• pp.120-122
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• 2007

3성분계 $Ti-C_x-N_{1-x}$ 코팅막은 AIP(Arc Ion Plating)법에 의해 -25V의 바이어스와 $300^{\circ}C$의 분위기에서 스테인리스 스틸 기판 위에 증착시켰다. $Ti-C_x-N_{1-x}$ 코팅막 안의 탄소(carbon)는 유입가스 비 $CH_4/(CH_4+N_2)$를 변화시키며 합성하였다. 탄소(carbon)가 증가함으로써, $Ti-C_x-N_{1-x}$ 코팅막의 미세경도는 TiN 코팅막의 20 GPa로부터 x=0.52에서 최대 약 32 GPa로 측정되었다. 또한, 미세구조는 잔류응력과 관련 있으며 탄소 함량에 따라 평균마찰계수가 크게 감소하였다.

• Journal of Food Hygiene and Safety
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• v.28 no.1
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• pp.63-68
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• 2013

Ethyl carbamate (EC) is a contaminant generated in the fermentation processes of various fermented foods. In this study, residue levels of EC in 95 alcoholic beverage samples were determined by using Gas Chromatography/Tandem Mass Spectrometry (GC/MS/MS). All the samples were purified by a liquid-liquid extraction (LLE) method using dichloromethane. The LLE method enables an improvement in time and cost to detection and specificity over the conventional extraction methods. The limits of detection and quantification (LOD and LOQ) to analyze EC were 1.3 and 4.0 ng/mL, respectively. The recovery rates of EC were ranged from 90.0 to 97.5% at the levels of 50, 100, and 500 ug/L. Among traditional grain-based alcoholic beverage samples (n = 34), the average residue levels of EC in takju, yakju, and cheongju were 0.63, 7.01, and 14.11 ug/L, respectively. Among fruit-based alcoholic beverage samples (n = 48), those of EC in japanese apricot spirits, bokbunjaju, grape wines, and other fruit wines were 79.18, 1.66, 2.64, and 2.39 ug/L, respectively. Among distilled or diluted alcoholic beverage samples (n = 13), those of EC in soju (distilled or diluted), general distillates, liquors, and brandies were 0, 3.30, 8.20, and 8.52 ug/L, respectively. Therefore, this study reports that the residue levels of EC in the alcoholic beverages, distributed in the current domestic markets, did not reach its maximum allowed levels of 30 and 400 ug/L established for grape and fruit wines in Canada, respectively.

• The Korean Journal of Pesticide Science
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• v.11 no.2
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• pp.95-105
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• 2007

The aim of this study was to determine the residual amounts of PAHs in environmental samples such as crop, soil and water collected from paddy, upland fields and forestlands near industrial zone and/or a thermal power plant in South Korea. All of the samples were analyzed by GC-mass spectrometer. The average contents of total PAHs in soil samples were 140.2 ${\mu}g\;kg^{-1}$ and the range was from 4.3 to $662.9{\mu}g\;kg^{-1}$. The detection of benzo(a)anthracene, chrysene, benzo(b)fluoranthene, benzo(k)fluoranthene, benzo(a)pyrene and dibenzo(a,h) anthracene which have strong carcinogenecity was ranged from 14.2 to 167.8 ${\mu}g\;kg^{-1}$. The residual amounts and detection frequency of PAHs in soil samples from the iron and heavy industrial areas near Pohang and Busan were 3-folds more than those of the other areas. Amounts of PAHs in upland soil samples was 1.5 folds higher than those of paddy soil samples, suggesting that it may be related to the content of organic matter in soil. The average contents of total PAHs in crop samples were 9.7 ${\mu}g\;kg^{-1}$ which ranged from 4.5 to 52.2 ${\mu}g\;kg^{-1}$. However, the residual amounts of PAHs in water samples were not detected. These results showed that soils and crops were slightly contaminated with PAHs. Therefore, the investigation should be continued for evaluating a safety or risk assessment through expansion of regions and crops.