• Korean Journal of Remote Sensing
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• v.16 no.3
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• pp.221-233
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• 2000

An intertidal topography is continuously changed due to morphodynamics processes. Detection and measurement of topographic change for a tidal flat is important to make an integrated coastal area management plan as well as to carry out sedimentologic study. The objective of this study is to generate intertidal DEM using leveling data and waterlines extracted from optical and microwave remotely sensed data in a relatively short period. Waterline is defined as the border line between exposed tidal flat and water body. The contour of the terrain height in tidal flat is equivalent to the waterline. One can utilize satellite images to generate intertidal DEM over large areas. Extraction of the waterline in a SAR image is a difficult task to perform partly because of the presence of speckle and partly because of similarity between the signal returned from the sea surface and that from the exposed tidal flat surface or land. Waterlines in SAR intensity and coherence map can effectively be extracted with MSP-RoA edge detector. From multiple images obtained over a range of tide elevation, it is possible to build up a set of heighted waterline within intertidal zone, and then a gridded DEM can be interpolated. We have tested the proposed method over the Gomso Bay, and succeeded in generating intertidal DEM with relatively high accuracy.

• Journal of Food Hygiene and Safety
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• v.34 no.3
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• pp.263-268
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• 2019

Methanol is a toxic alcohol used in various products such as antifreeze, detergent, disinfectant and industrial solvent. In the human body, methanol is oxidized to formaldehyde and formic acid, which can lead to metabolic acidosis, optic nerve impairment, and death. In this study, the methanol levels in detergents (n=191) and rinse aids (n=13) were analyzed by gas chromatography-headspace-mass spectrometry (GC-HS-MS). Limit of detection was 1.09 mg/kg, accuracy and precision were 91.1-97.9% and <10%, and it was suitable for quantitative analysis. This analysis method was simple and fast with a higher recovery rate than the conventional MFDS (Ministry of Food and Drug Safety) method of diluting the sample in water and putting it in a headspace vial.

• Journal of the Korean Chemical Society
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• v.65 no.6
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• pp.433-440
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• 2021

Surfactants are organic compounds that have both hydrophilic and non-polar parts in one molecule, classified as non-ion, anion, cation, and amphoteric surfactants according to the charge of hydrophilic parts in aqueous state. A trace amounts may remain when vegetables and fruits are washed using type1 detergent (Vegetable and fruit detergent), and there is a possibility of exposure to the human body through ingestion. This study developed the simultaneous analysis method for 5 surfactants with LC-MS/MS for analysis of detergent residues after washing vegetables and fruits with detergent. The mobile phase used distilled water and acetonitrile containing 50 mM ammonium formate and 0.1% formic acid and was analyzed using a gradient method using XBridge BEH C8 column. The accuracy of the established method was 83.9-112.1%, and the precision was less than 20%. The detection limit was 7.0 (SLS) to 29.0 (SLES-N3) ㎍/L, and the correlation coefficient (r²) of calibration line regression was greater than 0.99, it is considered suitable for the analysis of trace amounts of surfactant components remaining in vegetables and fruits.

• Economic and Environmental Geology
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• v.50 no.5
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• pp.341-352
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• 2017

Along with Cs-137 (half-life: 30.17 years), Sr-90 (half-life: 28.8 years) is one of the most important environmental monitoring radioactive elements. Rapid and easy monitoring method for Sr-90 using Laser-Induced Breakdown Spectroscopy (LIBS) has been studied. Strontium belongs to a bivalent alkaline earth metal such as calcium and has similar electron arrangement and size. Due to these similar chemical properties, it can easily enter into the human body through the food chain via water, soil, and crops when leaked into the environment. In addition, it is immersed into the bone at the case of human influx and causes the toxicity for a long time (biological half-life: about 50 years). It is a very reductive and related with the specific reaction that makes wet analysis difficult. In particular, radioactive strontium should be monitored by nuclear power plants but it is very difficult to be analysed from high-cost problems as well as low accuracy of analysis due to complicated analysis procedures, expensive analysis equipment, and a pretreatment process of using massive chemicals. Therefore, we introduce the Laser-Induced Breakdown Spectroscopy (LIBS) analysis method that analyzes the elements in the sample using the inherent spectrum by generating plasma on the sample using pulse energy, and it can be analyzed in a few seconds without preprocessing. A variety of analytical plates for samples were developed to improve the analytical sensitivity by optimizing the laser, wavelength, and time resolution. This can be effectively applied to real-time monitoring of radioactive wastewater discharged from a nuclear power plant, and furthermore, it can be applied as an emergency monitoring means such as possible future accidents at a nuclear power plants.

• Journal of Applied Biological Chemistry
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• v.61 no.3
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• pp.297-304
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• 2018

Coptis chinensis is used in oriental medicine for soothing, anti-inflammation, antimicrobial and antipyretic properties, and its main ingredient berberine is known to have strong antibacterial activity. In this study, we investigated the anti-microbial effect of hot water extract of Coptis chinensis (CW) on skin related microorganism and the airborne microbe, the antifungal effects of fungi, which are frequently detected in residential environments. CW showed antibacterial effect against Propionibacterium acnes, Staphylococcus aureus and Staphylococcus epidermidis, against the airborne microbe, which was collected in four different places. At the concentration of 100 mg/mL, the antimicrobial activity continued for 42 days, showed heat stability without change in the antimicrobial activity even after heat treatment. The MIC and MBC of CW against S. aureus was 0.03, 0.05 mg/mL, against S. epidermidis was 0.50, 0.75 mg/mL and against P. acne was 0.10, 0.15 mg/mL. As a result of measuring the MIC of four kinds of fungi with high detection frequency in the surrounding environment, Gliocladium virens was 65 mg/mL by determined as MIC which can inhibit one hundred percent of mycelial growth. The concentration 90 mg/mL was determined as MIC against Aureobasidium pullulans and 100 mg/mL against Penicilium pinophilum and Chaetomium globosum. CW was considered a safe extract that showed no irritation even in the ocular mucous membrane irritation evaluation test, a patch test. Therefore, these results suggest that Coptis chinensis has antimicrobial, antifungal and safety on human body and can be applied to the development of materials for cosmetic and residential environment industries.