• 한국자기학회:학술대회 개요집
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• 한국자기학회 2007년도 The 1st International Symposium on Advanced Magnetic Materials
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• pp.327.1-327.1
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• 2007

• Advances in environmental research
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• 제4권1호
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• pp.39-48
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• 2015

Bisphenol A is widely used in plastic and other industrial consumer products. Release of bisphenol A and its analogues into the aquatic environment during manufacture, use and disposal has been a great scientific and public concern due to their toxicity and endocrine disrupting effects on aquatic wildlife and even human beings. More recent studies have shown that these alkylphenols may affect the molting processes and survival of crustacean species such as American lobster, crab and shrimp. In this study, we have developed gas chromatography with flame ionization detection (GC-FID) and gas chromatography-mass spectrometric (GC-MS) methods for the determination of bisphenol A and its analogues in shrimp Macrobrachium rosenbergii, blue crab Callinectes sapidus and American lobster Homarus americanus samples. Bisphenol A, 2,4-bis-(dimethylbenzyl)phenol and 4-cumylphenol were found in shrimp in the concentration ranges of 0.67-5.51, 0.36-1.61, and < LOD (the limit of detection)-1.96 ng/g (wet weight), and in crab of 0.10-0.44, 0.13-0.62, and 0.26-0.58 ng/g (wet weight), respectively. In lobster tissue samples, bisphenol A, 2-t-butyl-4-(dimethylbenzyl)phenol, 2,6-bis-(t-butyl)-4-(dimethylbenzyl)phenol, 2,4-bis-(dimethybenzyl)phenol, 2,4-bis-(dimethylbenzyl)-6-t-butylphenol and 4-cumylphenol were determined at the concentration ranges of 4.48-7.01, 1.23-2.63, 2.71-9.10, 0.35-0.91, 0.64-3.25, and 0.44-1.00 ng/g (wet weight), respectively. At these concentration levels, BPA and its analogs may interfere the reproduction and development of crustaceans, such as larval survival, molting, metamorphosis and shell hardening.

• 한국진공학회지
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• 제17권1호
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• pp.73-79
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• 2008

투명 전도성 산화물 전극(transparent conductive oxide electrodes)에 적용하기 위하여 RF 마그네트론 스퍼터링 방법에 의해 유리 기판 위에 산화아연 박막을 증착하였다. 투명 전극으로써 응용되기 위한 최적의 조건으로 기판온도를 상온으로 유지하고 RF power 200 W, 타겟과 기판사이의 거리(Dts)가 30 mm일 때 증착된 산화아연 박막으로부터 가장 낮은 비 저항값($7.4{\times}10^{-3}{\Omega}cm$)을 얻어 낼 수 있었으며, 85% 이상의 높은 투과율을 만족하는 박막을 얻을 수 있었다. 실질적인 소자로써의 응용을 위해 photo lithography를 통한 pattern을 형성, 습식 식각을 통하여 그 특성을 알아보고자 하였다. 습식 식각에서 사용된 식각용액(etchant)으로는 다양한 산 용액(황산, 옥살산, 인산)을 사용하였으며, 산의 농도 변화에 따른 식각특성과 식각시간 및 식각 이미지(표면형상)의 변화를 알아보았다. 결과적으로 산화아연의 습식식각은 산의 종류와 무관하게 산 용액의 농도(즉, pH)에 크게 의존하며, pH가 증가함에 따라 식각율이 지수함수적으로 감소하고 아울러 다양한 식각 이미지가 나타남을 최초로 고찰할 수 있었다.

• 공업화학
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• 제32권6호
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• pp.659-663
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• 2021

반도체 제조공정에서 발생하는 미세먼지와 질소산화물 동시처리를 위하여 오존산화, 습식중화 및 습식전기집진 기술들을 직접화한 10 CMM급 복합오염물질 제거시스템을 개발하였으며, NOx 제거효율 증대를 위한 공정변수 제어 및 최적화를 진행하였다. 특히, 전원공급장치를 포함한 습식전기집진장치 핵심부품 안정성 평가를 위해 30일 동안의 장기운전도 병행하였다. 오존산화 기반 DeNOx 공정에서 가장 중요한 운전변수인 O₃/NO 비율은 1.5 부근에서 최적화하였으며, 습식중화 공정의 운전변수를 최적화하여 중화반응에 의한 제거효율 기여도를 확인하였다.

• Asian Journal of Atmospheric Environment
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• 제11권4호
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• pp.270-282
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• 2017

To evaluate the deposition amount on a ground surface, mesoscale numerical models coupled with atmospheric chemistry are widely used for larger horizontal domains ranging from a few to several hundreds of kilometers; however, these models are rarely applied to high-resolution simulations. In this study, the performance of a dry and wet deposition model is investigated to estimate the amount of deposition via computational fluid dynamics (CFD) models with high grid resolution. Reynolds-averaged Navier-Stokes (RANS) simulations are implemented for a cone and a two-dimensional ridge to estimate the dry deposition rate, and a constant deposition velocity is used to obtain the dry deposition flux. The results show that the dry deposition rate of RANS generally corresponds to that observed in wind-tunnel experiments. For the wet deposition model, the transport equation of a new scalar concentration scavenged by rain droplets is developed and used instead of the scalar concentration scavenged by raindrops falling to the ground surface just below the scavenging point, which is normally used in mesoscale numerical models. A sensitivity analysis of the proposed wet deposition procedure is implemented. The result indicates the applicability of RANS for high-resolution grids considering the effect of terrains on the wet deposition.

• Bulletin of the Korean Chemical Society
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• 제35권11호
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• pp.3280-3288
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• 2014

Alkoxyalcohols are used as solvents or preservatives in various consumer products such as wet wipes. The metabolites of alkoxyalcohols are known to be chronically toxic and carcinogenic to animals. Thus, an analytical method is needed to monitor alkoxyalcohols in wet wipes. The aim of this study was to develop a simultaneous analytical method for 14 alkoxyalcohols using headspace gas chromatography coupled with mass spectrometry to analyze the wet wipes. This method was developed by comparing with various headspace extraction parameters. The linear calibration curves were obtained for the method ($r^2$ > 0.995). The limit of detection of alkoxyalcohols ranged from 2 to $200ng\;mL^{-1}$. The precision of the determinative method was less than 18.20% coefficient of variation both intra and inter days. The accuracy of the method ranged from 82.86% to 119.83%. (2-Methoxymethylethoxy)propanol, 2-phenoxyethanol, and 1-phenoxy-2-propanol were mainly detected in wet wipes.

• 한국응용과학기술학회지
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• 제30권3호
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• pp.518-527
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• 2013

5,6-dihydroxyindole was easily oxidation with air and light Conditions. Availability of 5,6-dihydroxyindole was studied for hair dye as a precursor of melanin. This study used wet and dry coating process to stabilize 5,6-dihydroxyindole. In wet process used dimethicone and cyclometicone, the 5,6-dihydroxyindole had darkened through the drying process at $58^{\circ}C$. Wet coating process was inappropriate to stabilize the coating. In dry coating process, shea butter coating was stable until 3 days. Dextrin palmitate was most efficient ingredient to prevent oxidation by sun light and air until 7days. Oxidation test with 1.0% and 1.5% of dextrin palmitate was not different under conditions of sun light and air and was not dependent on contents. Vitamin E acetate under conditions of sun light and air, there were no significant effect in preventing oxidation.

• 한국펄프종이공학회:학술대회논문집
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• 한국펄프종이공학회 2006년도 PAN PACIFIC CONFERENCE vol.2
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• pp.191-195
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• 2006

Multivariate data analysis tools were used to improve the understanding of the wet end chemistry and white water system of the Papermill at NorskeCanada Crofton Division. Specifically, the analysis was aimed at identifying what variables were contributing to increased retention aid use and wet end instability. Several models were developed using data sets with up to 88 process variables and over 3000 observations. It was found that increased retention aid use was driven primarily by PCC and TMP usage as well as the addition of Alaskan White Spruce to the TMP furnish.

• 공업화학
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• 제8권6호
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• pp.1000-1005
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• 1997

참치 뼈로부터 추출한 hydroxyapatite[$Ca_{10}(PO_4)_6(OH)_2$]를 습식법으로 분쇄한 후 여러 온도로 고상반응시킨 세라믹 소결체의 특성을 고찰하였다. Hydroxyapatite소결체의 밀도는 $1350^{\circ}C$에서 약 $2.93g/cm^3$으로서 이론치의 $3.21g/cm^3$과 유사하였다. $1300^{\circ}C$ 이하의 소결온도에서는 hydroxyapatite가 결정상으로 나타났으며, 온도가 증가할수록 hydroxyapatite의 분해에 따른 whitlockite[$Ca_3(PO_4)_2$]의 결정상이 관찰되었다. 소결채의 미세구조는 발달된 입계들 사이에 폐기공들이 분포하였다. $1350^{\circ}C$의 소결시편 평균강도는 58MPa로 나타나 관절연골(articular cartilage)의 최대강도인 40MPa보다 우수한 것으로 나타났다.

• 한국환경과학회지
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• 제18권7호
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• pp.803-810
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• 2009

Concentrations of dioxins, furans and dioxin-like polychlorinated biphenyls (DL-PCBs) were determined in crucian carp collected from eight locations mainly along the Nakdong River during 2004. Total dioxin concentrations which include concentrations of dioxins, furans and DL-PCBs ranged from 0.053 to 0.614 pg WHO-TEQ $g^{-1}$ wet wt. with a mean of $0.342{\pm}0.213$ pg WHO-TEQ $g^{-1}$ wet wt. The proportions of dioxins, furans and DL-PCBs to total dioxin TEQ were 4%, 12% and 84%, respectively. The results suggest that concentrations of dioxin-like polychlorinated biphenyls should be determined when total dioxin TEQ accumulated in freshwater fish is investigated.