• Korean Journal of Remote Sensing
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• v.36 no.6_3
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• pp.1691-1710
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• 2020

We measured PM2.5 and PM10 (particulate matter less than 2.5 ㎛ and 10 ㎛ in diameter, respectively) simultaneously at 16 locations around an elementary school and classrooms in Busan and Pyeongtaek, South Korea. In this study, we compared the results of this field intensive with those in the literature (144 cases of 30 studies), focusing on I/O (Indoor/Outdoor) ratios. We also reviewed the results of previous studies, categorizing them into related sub-categories for indoor-activities, seasons, building-uses, and the surrounding environment. We conclude that indoor PM10 is affected more by indoor-sources (e.g., physical activities) than PM2.5 in the absence of combustion sources like smoking and cooking. Additionally, PM10 and PM2.5 likely have different indoor-outdoor infiltration efficiencies. Conclusively, PM10 in classrooms can be more sensitively affected by both indoor activities and ambient concentrations, and mechanical ventilation can be more efficient in reducing PM concentrations than natural ventilation.

• Journal of the Korean Institute of Gas
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• v.24 no.5
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• pp.29-38
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• 2020

It is practically difficult to accurately measure the temperature and concentration of a large combustion systems at industrial sites in real time. Temperature measurement using thermocouple, which are mainly used, is a point-measuring method that is less accurate and less reliable to analyze the wide area range of inner combustion system, and has limitations to internal accessibility. In terms of concentration analysis, most measurement methods use sampling method, which are limited by the difficulty of real-time measurement. As a way to overcome these limitations, laser-based measurement methods have been developed continuously. Laser-based measurement are line-average measurement methods with high representation and precision, which are beneficial for the application of large combustion systems. In this study the temperature and concentration were measured in real time by water vapor and oxygen generated during combustion using Tunable Diode Laser Absorption Spectroscopy (TDLAS). The results showed that the average temperature inside the combustion system was 1330℃ and the mean oxygen concentration was 3.3 %, which showed similar tendency with plant monitoring data.

• Journal of Korea Water Resources Association
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• v.32 no.6
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• pp.751-762
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• 1999

In this study, a 1-D laboratory experiment was conducted to investigate the characteristics of transient unsaturated solute transport by using two kinds of soils of which properties were known by test. Especially the TDR method which is proposed in this study was used to measure water content and solute concentration. As results, in the transient flow, the wetting front moves down rapidly, and the distribution of solute concentration near the wetting front showed the similar type of the water content distribution(semi-bell type). A numerical model HYDRUS was used to compare with the experimental results. Numerical results for the water movement are similar to experimental result. However, numerical results of the distribution of solute concentration are more scattered than experimental results. It means that measured dispersivity, numerical dispersion, adsorption coefficient, and soil sample size etc. should be considered in order to determine the dispersivity used in the numerical model. The present measuring method was proved to be superior to other formula and to be an available method to apply to solute transport test. The measuring error of the developed method is estimated smaller than 10% while water content is larger than 0.15.

• Journal of the Korean earth science society
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• v.21 no.1
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• pp.51-58
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• 2000

This study was performed to accumulate database for natural sulfur emissions in the Yellow Sea region of Korea. The atmospheric concentrations of dimethylsulfide(DMS) were measured during two intensive field experiments (April and September 1999) from Duk-Juk Island located in the Yellow Sea. Ship-measurement of DMS was made additionally between Chungdo(China) and Inchun(Korea) across the Yellow Sea during June 1999. The mean(and ISD) of DMS concentrations in Duk-Juk Island during two field campaigns was $24.0{\pm}40.5$(n=40, April) and $61.1{\pm}37.9$ pptv(n=35, September), respectively. The atmospheric DMS measured from ship experiments was generally low and close to the background concentrations in the open sea area. The temporal distributions of DMS concentration were complicated in some sense but comparable to those of ambient meteorological parameters. On the basis of our measurements of atmospheric DMS(and evidence found from previous studies), the sea-to-air flux of DMS in the Yellow Sea is estimated to be about 4Gg S/yr. This amount of natural S emissions is relatively lower than the estimates derived for Cheju Island. Therefore, additional experiments may be desperate to derive more reliable figures for natural sulfur emissions in the Yellow Sea region.

• The Korean Journal of Zoology
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• v.35 no.4
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• pp.526-533
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• 1992

포유류 배아의 착상기작을 규명하고자 본 연구에서는 착상시기에 수정된 배아가 착상부위를 어떻게 인식하는 지 그리고 착상부위의 분화유발요인이 무엇인지를 조사하였다. 착상시기(임신 제6일)와 착상후 초기배아 발생기간(임신 제9일)중 혈청내 estradiol (E2)과 Progesterone(P4)의 농도를 측정하였으며, 자궁내막 조직을 착상부위 (antimesome trium)와 비 착상부위(mesometrium)로 분리하여 P4의 수용체 농도를 측정하였다. 혈청내 E2의 농도는 임신 제6일군에서 E2처리군에서 가장 높았으며, 임신 제9일에서는 intact 대조군에서 가장 높고 제9일의 모든 실험군의 농도는 임신 제6일군보다 높았다. 혈청내 P4 농도는 임신 제6일과 9일에서 다같이 대조군에서 가장 높으며 처리군 중에서는 P4처리군에서 높아지고 있다. P4 농도 역시 임신 제9일의 모든 실험군에서 제6일의 실험군보다 높았다. P4수용체 농도는 착상부위가 비 착상부위보다 높으며, 대조군(P < 0.01)과 P처리 군(P < 0.05)에서는 유의한 차이로 비 착상부위보다 높았다. 자궁내막조직 착상을 위한 분화에는 P4의 영향이 크며 P4의 혈청내 농도와 핵의 수용체 농도는 모든 실험군에서 상응하는 관계를 나타내었다. 이 결과는 앞서 일차적으로 발표한 알카리성 phosphatase (ALPase) 활성과도 상응하는 것이다.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2004.04a
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• pp.235-238
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• 2004

유류 오염토양에 대한 과산화수소의 화학적 고도산화에 대한 실험실 및 현장 적용 가능성을 타진하였다. 현장 오염토양 10g에 각각 과산화수소(34.5%) 원액을 중량비로 0.3%, 0.6%, 1.0%, 2.0%를 처리하여 혼합 후 실험실에서 1일 반응 후 TPH 농도를 분석하였다. 분석결과 토양 대비 2.0%의 과산화수소를 투입한 처리구에서 가장 높은 복원 효율을 측정할 수 있었고 2.0%까지의 투입농도에서 미생물의 농도 변화는 측정되지 않았다. 오염된 토양에 과산화수소를 오염 토양 중량 대비 2%를 분무기로 살포 후 로타리가 설치된 경작 장비로 뒤집기 수행하여 1일 후 오염토양의 오염농도를 분석한 결과 초기 TPH 5,365ppm의 농도가 2,317ppm으로 56.8% 복원된 것을 확인할 수 있었다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.4 no.3
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• pp.257-259
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• 2003

본 논문은 다이오드 레이저와 광 다이오드를 사용한 이중 빗살형 다이오드 레이저 비색 분광기를 개발하여 항균 성분의 양이온 계면 활성제로 널리 사용되고 있는 cetylpyridinium chloride(CPC)의 농도를 측정하였다 분광기의 안정도는 광원의 세기, 감도, 재현성을 측정한 예비 실험을 통하여 검증이 되었다 또한 상용화된 UV/VIS분광기와의 비교 결과를 나타내었다. 다이오드 비색 분광기는 3×10/sup -5/M에서 1.1×10/sup -4/M의 CPC 농도 범위에서 0.9635의 상관계수를 나타내었다. 이러한 결과는 CPC의 농도 분석을 위한 간편한 다이오드 레이저 비색 분광기 개발의 가능성을 나타내었다.

• Korean Journal of Ecology and Environment
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• v.37 no.1 s.106
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• pp.106-111
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• 2004

Fecal coliform bacteria is one of the most common cause of water quality impairments in Virginia, USA. Instream concentrations of fecal coliform (FC) bacteria were routinely monitored to assess surface water quality of the Polecat Creek watershed. Median concentration in water samples collected from 1995 to 2000 ranged from 80 cfu/100 mL to t 70 cfu/100 mL, while geometric mean concentrations ranged from 81 cfu/100 mL to 141 cfu/100 mL. The dilution and deposition by Lake Caroline may cause to lower FC concentration at monitoring site QPB, as compared FC concentration at QPD. Higher in-stream FC concentration occurred during the summer period(June-August), and lower concentration typically occurred during the winter period (December-February). This is due to more cattle in streams, and greater survival and regrowth of FC bacteria under warmer condition. The findings of this study can be helpful in planning the water quality monitoring program to avoid the inaccurate assessment of water quality due to the timing of sample collection.

• Applied Chemistry for Engineering
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• v.9 no.6
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• pp.857-863
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• 1998

A simple and new experimental method for determination of lysozyme-M. lysodeikticus cell lysis reaction and lysozyme activity was suggested using Beer's law. The UV transmittance of the solution changed with the concentration of M. lysodeikticus and the relationship between the UV transmittance and M. lysodeikticus cell concentration followed Beer's Law. In addition, it was experimentally proven that the UV transmittance of the solution was not influenced by the lysozyme concentration and product of the lysis reaction. During the lysozyme-M. lysodeikticus cell lysis reaction, thus, M. lysodeikticus cell concentration in the solution could be measured in-situ by UV-spectrophotometer. By using these experimental data, kinetic Parameters of the Michaelis-Menten equation for the lysozyme-M. lysodeikticus cell 1ysis reaction was simply determined The maximum reaction rate constant ($k_3$) and Michaelis-Menten constants were $0.1734sec^{-1}$ and $9.83{\times}10^{-6}M$ respectively. The activity of the lysozyme could also be obtained with this experiment because the lysis reaction rate of the 1ysozyme depended on its activity.

• Food Science and Preservation
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• v.6 no.2
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• pp.216-220
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• 1999

Lipoxygenase(LOX) activity of black rice(Chindo) was measured by spectrophotometric method at In m. Studies at different pH levels revealed that the optimal activity was exhibited at pH 7.0 with 24.97 unit/mg. Enzyme activity was tested at different concentration of the substrate. The apparent Vmax and Km values were determined from the Lineweaver-Burk plot to be 53.85 unit/mg and 0.21 mM. Enzyme activity due to storage temperature (-40, 4 and 25$^{\circ}C$) and period were decreased at all storage temperature. LOX activity of black rice was significantly decreased during the microwave heating.