• Journal of Korean Society of Environmental Engineers
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• v.30 no.7
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• pp.721-728
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• 2008

DBPs(Disinfection By-Products) are most formed through the reactions between chlorine and NOM(Natural Organic Matter) in water treatment. In this study, occurrence of DBPs including THMs(Trihalomethanes) is evaluated. Also, influencing factors by the seasons and raw water quality were investigated for correlation among them and the characteristics of THMs formation by prechlorination process. This study investigated the operation condition for THMs removal depending on raw water quality. Water treatment plant from intake station to gauging well flows for about 10 hours in Y Water Supply Office. It is limited to control of THMs formation because of excessive reaction time between chlorine and THMs precursors in the intake station. Therefore, as multi-points prechlorination from intake station to gauging well, THMs formation was decreased in the water treatment, and it was willing to prevent overdosage of chlorine. The concentration of THMs was 0.021 mg/L in the summer, 0.015 mg/L in the winter, respectively. Also, THMs formation showed that 0.013 mg/L in the water of gauging well after prechlorination, 0.014 mg/L in the flocculation/sedimentation/filtration, 0.016 mg/L in the water after postchlorination, respectively. THMFP(Trihalomethane Formation Potential) removed 42.7% and 50% through the flocculation/sedimentation and filtration, respectively, and it is similar TOC removal efficiency. In this study, multi-points prechlorination from intake station to gauging well decreases in contact time and concencrations of NOM and chlorine. Also, it decreases in THMs and amount of chlorine uesd. In the result of multi-points prechlorination in the summer, the concentration of THMs was 0.013mg/L in the treated water. In view of these facts, THMs formation can be decreased approximately 50%.

• Korean Journal of Remote Sensing
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• v.34 no.5
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• pp.763-775
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• 2018

In this study, the effects of wind fences on the dispersion of the particles emitted from a constructing site located in the building-congested area in Busan, Korea, using geographic information system (GIS) and a computational fluid dynamics (CFD) model. We averaged the wind speeds observed for 10 years at the Busan automated synoptic observing system (ASOS) and we used the averaged wind speed as the wind speed at the reference height (10 m above the ground level). The numerical simulations were performed for 16 inflow directions, before and after the construction of wind fences with the heights of 5 m and 10 m (total 48 simulations). The detailed flows were analyzed for the northeasterly and south-southwesterly cases which predominantly observed at the Busan ASOS. In the northeasterly case, high concentration appeared at the elementary school next to the construction site due to transport by the airflow coming from the northeast. In the 5-m wind fence case, the wind speeds were slightly weaker and the spread of the fugitive dust was slightly less than those in the no wind fence case. In the 10-m wind fence case, the dust concentration at the elementary school has the maximum reduction of 37%. In the south-southwesterly case, the flow pattern became complicated in the construction site due to the terrain and buildings. Fugitive dust was stagnant at the south side of the construction site but rather spread to the north, increasing the concentration at the elementary school. After the wind fence was built, the concentrations inside the construction site became high as the wind speeds decreased inside, but, the concentrations in the elementary school rather decreased.

• Journal of the Korean Applied Science and Technology
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• v.32 no.1
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• pp.136-147
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• 2015

As it carry out RPS(Renewable Portfolio Standards), power producers are using the power bio-fuel oil to meet their RPS quota. In this study, we test the quality characteristics of raw materials for power bio-fuel oil and the property changes of power bio-fuel oil by the kind of feedstocks. The power bio-fuel oil and feedstocks were analyzed for item of quality standard such as acid number, viscosity and metal contents. And it was analyzed for composition distribution by FT-IT and HPLC. Such as low priced palm oil series has high acid number and ash contents due to high free-fatty acid and metal contents. And by-product of biodiesel have a tendency of high viscosity. The fuel properties of power bio-fuel oil, such as viscosity, acid number and metal contents are correlated with the constituent and the mixing ratio of the feedstocks.

• Korean Journal of Food Science and Technology
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• v.43 no.6
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• pp.675-682
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• 2011

This study was conducted to monitor the concentrations of 24 anti-impotence drugs and their analogues in various foods and dietary supplements, with the aim of ensuring the safety of the foods and supplements. The measurements were done in 226 samples using high performance liquid chromatography/photodiode array detector (HPLC/PDA) and liquid chromatography-electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS). Five male sexual function enhancing products have been detected as follows: acethylvardenafil (21,476 mg/kg; 15 mg/capsule from one sample), sildenafil (52,778 mg/kg, 29 mg/capsule in one sample; 71,535 mg/kg, 48 mg/capsule in one sample), and tadalafil (9,772-55,545 mg/kg, 6-33 mg/capsule in four samples). A sustainable monitoring of anti-impotence drugs and their analogues in various foods and dietary supplement is recommended.

• Journal of Korean Society of Environmental Engineers
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• v.32 no.2
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• pp.155-164
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• 2010

Emission from biomass combustion such as meat charbroiling is an important source of organic aerosol. Since source profiles are necessary input profiles for source apportionment of aerosol by a chemical mass balance model, meat cooking organic source profiles are developed by measuring organic marker compounds, including palmitic acid, stearic acid, oleic acid and cholesterol as well as PAH compounds. Emissions from meat and pork charbroiling are collected on quartz filters with a PM10-high volume sampler, extracted with organic solvents, derivatized with diazomethane/TMS and analyzed by GC/MS isotope dilution method. Organic and elemental carbon are also analyzed by an OCEC analyzer. Wt.% of cholesterol to the organic carbon(OC) content from beef and pork charbroiling is only 0.056 and 0.062, but wt. % of all saturated fatty acids to the OC content from beef and pork charbroiling is 2.727 and 2.022, and the wt% of all unsaturated fatty acids to the OC content is 0.278 and 0.438, respectively. Content of total PAH compounds to the OC content from beef charbroiling is higher than that from pork charbroiling, and those are 0.116 wt% and 0.044 wt%. Among PAH compounds benzo(a)pyrene as a single compound is account for 0.0071 wt% and 0.0023 wt% of OC content from beef and pork charbroiling. Ratios of marker compound to cholesterol are calculated, and those values are in good agreement with the values already reported at the food cooking emission, indicating that they can be used as organic source profiles for the apportionment of organic aerosol.

• Journal of Korean Society of Forest Science
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• v.111 no.4
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• pp.490-501
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• 2022

In this study, the isoprene and terpene emissions from 32 major urban tree species were investigated. We conducted sampling using a dynamic enclosure system between June and July 2021. Seedlings aged < three years were enclosed in a chamber consisting of a 400 L transparent Tedlar bag. The air flow from the outlet of the chamber was sampled using Tenax-filled sorbent tubes under standard conditions (temperature: 30°C; PAR: 1,000 μmol/m²/sec). A thermal desorption gas chromatography/mass spectrometry system was used to analyze the following 38 biogenic volatile organic compounds: isoprene, monoterpenes, sesquiterpenes, oxygenated monoterpenes, and oxygenated sesquiterpenes. Isoprene emitters included Quercus mongolica, Salix koreensis, Robinia pseudoacacia, and Salix chaenomeloides. Monoterpene emitters included Pinus strobus, Cedrela sinensis, and Cercis chinensis. The monoterpene emission profiles were dominated by á-pinene, myrcene, camphene, and limonene. The predominant oxygenated monoterpene and oxygenated sesquiterpene were eucalyptol and caryophyllene oxide, respectively. For all species, the contributions of sesquiterpenes and oxygenated sesquiterpenes were relatively low.

• Korean Journal of Food Science and Technology
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• v.42 no.2
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• pp.130-135
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• 2010

Picrate, enzyme-picrate and instrumental analysis methods using IC (Ion Chromatography) and HPLC (High Performance Liquid Chromatography) were compared for their effectiveness in determining cyanide in extracts of Maesil, which is classified as a harmful substance. First, the picrate method showed the shortest analysis time (about 5 hr). The color of picrate paper changed at 0.01 mg/$200\;mL\;CN^-$. However, it was difficult to detect cyanide from amygdalin of glucosides. Second, we performed a qualitative analysis for total cyanide (free cyanide and cyanide from amygdalin) by the enzyme-picrate method using $\beta$-glucosidase and a quantitative analysis by spectrophotometry. Finally, analysis of cyanide by IC and HPLC required the longest determining time (about 17 hr) as well as pretreatment for each free cyanide and amygdalin. These results suggest that enzyme-picrate is the most effective analysis method for the detection of cyanide in Maesil extracts.

• Proceedings of the Korean Society of Applied Pharmacology
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• 1994.04a
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• pp.269-269
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• 1994

GABA shunt에 관여하는 두 가지 효소인, GABA transminase와 Succinic semialdehyde reductase에 대한 단일 클론 항체를 생산하고 이들 항체의 특성을 살펴보았다. 소의 뇌에서 순수 정제된 효소를 동물에 주사한 후 immunodot-blot 분석법에 의하여 일차적으로 항체를 분비하는 hybridoma를 골라낸 후 생산된 단일 클론 항체가 특이적으로 이들 효소와 반응하는 가를 알아보기 위하여 Western blot 분석을 실시하였다. 뇌조직에서 추출한 총단백질을 SDS 전기영동법에 의하여 분리한 후 이들 항체를 처리한 결과, GABA-T에 대한 항체는 특이적으로 분자량이 50kDa에 해당하는 단백질 밴드만을 인지하였고 SSA reductase에 대한 항체의 경우 분자량이 34kDa 크기의 단백질 밴드와 반응하였다. 이들 분자량은 순수 정제된 소뇌의 효소 단백질의 크기에 해당하는 것을 확인하였다. 이들 소뇌의 효소에 대한 항체를 추적물체로 사용하여 다른 포유동물자 조류의 효소와 비교하는 cross-reactivity 연구를 수행하였다. 소, 돼지, 토끼, 쥐 (rat), 개, 고양이 그리고 닭의 뇌를 제거한 후 총단백질을 추출하고 Western blot을 해본 결과 GABA transaminase의 경우 조류를 제외하고 다른 포유동물에서는 같은 분자량의 단일 단백질 밴드를 확인하였고 SSA reductase의 경우 조류를 포함하는 모든 동물에서 같은 분자량의 밴드를 확인하였다 이상의 결과로 미루어 보아 포유류 뇌에 있는 이들 효소들은 변역학적으로 아주 유사하다고 사료된다.

• The Journal of Engineering Geology
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• v.4 no.2
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• pp.207-218
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• 1994

The natural constants of moving coil type geophone can be determined by free impedance and step force method. The former method was desirable for the measurement of natural frequency($f_o$), inertial mass(m) and damping factor($h_o$), but the latter method for sensitivity(G). In particular, the value by the latter method should be corrected for the noise by the long period movement of measurement device. The results of frequency characteristics from these constants operate the accelerometer and displacement system in the boundary of natural frequency.

• Proceeding of EDISON Challenge
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• 2016.03a
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• pp.292-294
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• 2016

이황화몰리브덴을 활용한 전계효과트랜지스터(Field Effect Transistor)는 채널 물질의 우수한 특성으로 차세대 저전력 고성능 스위치와 광전소자로 주목받고있다. Underlap 게이트 구조에서 게이트 길이(L_G), 절연체 두께(T), 절연체 상대유전율(${\varepsilon}_r$)에 따라 변화하는 소자특성을 분석하여 저전력 고성능 $MoS_2$ 전계효과트랜지스터를 위한 게이트 구조 최적화방법을 모색하였다. EDISON simulator 중 Tight-binding NEGF 기반 TMD FET 소자 성능 및 특성 해석용 S/W를 활용하여 게이트 구조에 따른 게이트 전압 - 드레인 전류 상관관계(transfer characteristic)를 얻고, Y-function method를 이용하여 채널 유효전하이동도(Effective Mobility), Sub-threshold Swing, on/off 전류비(on/off current ratio)를 추출하여 비교 분석하였다. 시뮬레이션으로 추출한 소자의 최대 채널 유효전하이동도는 $37cm^2V^{-1}s^{-1}$, on/off 전류비는 $10^4{\sim}10^5$, Sub-threshold Swing은 ~38mV/dec 수준을 보였다.