• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.15 no.3
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• pp.74-82
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• 2001

To reduce the maintenance expense and the possibility of electric outage and/or accident, which causes the decrease in stability and reliability of transmission/distribution line, most of all, accurate measurement for the degree of contamination should be preceded. But the conventional method (brush wiping method), which is recommended in IEC 60815, has sow significant problem in the aspect of man power, expense, error, and so forth. In this investigation, we purpose the development of a new type automatic measuring apparatus, which could measure the degree of contamination on the surface of insulator in outdoor condition. To design and evaluate the apparatus, a FLUX 2D is used, and various laboratory tests, artificial contamination tests, were carried to proof the actual performance. With the result of these effort, we can get the meaningful conclusion to develope a new type automatic apparatus for contamination measurement.

• 한국방재학회:학술대회논문집
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• 2008.02a
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• pp.827-830
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• 2008

Enterococcus is a fecal indicator bacterium and often used to indicate fecal contamination in the environment. Carbohydrates fermentation patterns of Enterococcus isolates were investigated as a way to differentiate the source of fecal contamination. Total 1826 Enterococcus isolates were obtained from cows, pigs, chickens, ducks, and humans in two geographically different locations. Distributions of carbohydrate fermentation patterns showed discrepancies among sources. This study suggest that the possibility of the use of Enterococcus in microbial source tracking.

• Korean Chemical Engineering Research
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• v.60 no.1
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• pp.20-24
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• 2022

In the process of long-term use of PEMFC (Proton Exchange Membrane Fuel Cells), chemical degradation of membrane electrode assembly (MEA) occurs due to corrosion of stack elements and contamination of supply gas. In this study, we investigated whether chemically degraded MEA can be recovered by acid washing. The performance was measured and compared in a PEMFC cell after contamination with iron ions and washing with an aqueous sulfuric acid solution. The performance was reduced by about 25% by 0.5 ppm iron ion contamination, and 97.1% performance recovery was possible by washing of 0.15 M sulfuric acid. The membrane resistance was increased due to iron ion contamination of the polymer membrane, and the ionic conductivity was restored by washing the iron ions from the membrane while minimizing the loss of the electrode catalyst by washing with a low-concentration sulfuric acid aqueous solution. The possibility of solving the decrease in durability caused by chemical contamination of PEMFC MEA by the acid washing was confirmed.

• Journal of the Korean Society of Safety
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• v.7 no.3
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• pp.22-29
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• 1992

Emulsion-type cometics contain many kinds of carbon and energy source i.e., vegetable oil, mineral oil and carbohydrate etc., those can be used as nutrients and caused contamination by microbials. Thereby we have to keep cosmetics from the possibility of contamination by microbials. From this viewpoint, the purpose of this study is to get the data necessary not only to prevent dermatopathia occurred by microbials but also to sustain the quality. In this experiment, we observed how many Staphylococcus aureus were grown in the prepared cosmetics with or without antiseptics so as to prevent contamination. When the contamination proceed, the stability of phase was disturbed and creaming phenomina was happened with some discoloration and bad smell. About 40 days after, the pH was changed from 7.6 to 6.5 and the refractive index of cosmetic raw materials were changed from 1.4415 to 1.4490(water : oil=70:30). By adding antiseptics Into prepared cosmetics, the number of Staphylococcus aureus with challenge test method were decreased to 7$\times$103 cell/ml. For the antibacterial effect against Staphylococcus aureus, p-hydroxy benzoic acid propyl ester in phosphoric acid buffer solution was the best.

• Biomedical Science Letters
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• v.29 no.4
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• pp.256-262
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• 2023

The purpose of this study is to investigate microbial contamination in water purifiers from two universities (A and B) in Chungcheong region and to evaluate about the harmfulness of the isolated bacteria to the human. The degree of microbiological contamination of six water purifiers at university A was investigated three times from July 2018 to September 2019, and nine water purifiers at university B were investigated in 2023. The isolated bacteria were biochemically identified using an API kit and Vitek-2 system, and then the bacteria were identified to the species level using MALDI-TOF MS. In addition, the possibility of human infection of the isolated bacteria was evaluated through a literature search. In July 2018 and September 2019, the number of bacteria isolated inside the faucet was below the acceptable standard for hot water, but exceed for cold water in all water purifiers. In January and September 2019, bacteria exceeding the acceptable standards were isolated nine times from the cold water of six water purifies (a total of 12 water purifiers). Bacteria identified by MALDI-TOF MS included anaerobic bacteria (Clostridium novyi, Clostridium themopalmarium etc.), Gram-positive bacilli (Microbacterium testaceum, Arthrobacter woluwensis etc.), and Gramnegative bacilli (Acinetobacter nosocomialis, Comamonas kerstersii etc.), which are difficult identify by biochemical methods. In conclusion, bacteria exceeding the acceptable standard were isolated from the cold water of most of the water purifiers. Most of the isolated bacteria were low-pathogenic bacteria from natural environment, but opportunistic bacteria that can cause infection in humans were also isolated from some water purifiers.

• Journal of the Korea Institute of Military Science and Technology
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• v.18 no.5
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• pp.582-593
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• 2015

For military training and course-of-action analysis, OneSAF Int'l version being used in ROK Army has a limited capability to simulate NBC(nuclear, biological, and chemical) damages. For high-fidelity NBC combat simulation, it is required to visualize NBC contamination dispersion in consideration of weather conditions and terrain characteristics. However, OneSAF itself handling interaction among thousands of combat entities cannot carry out a simulation of NBC contamination dispersion because it brings about an excess burden. To resolve this problem, this research aims to design simulation federation for analysis on NBC operational effects. After examining design consideration to connect OneSAF and a NBC contamination dispersion model, we design a federation architecture that facilitates the interaction between OneSAF and a NBC contamination dispersion model. Afterwards, we implement a federation interface to share simulation data by publish-subscribe pattern and to translate them into the proprietary format for each model. We prove the possibility of federation between both models, as showing that dispersion of NBC contaminated cloud and changes in concentration are reflected in OneSAF-based engagement simulation.

• Journal of Soil and Groundwater Environment
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• v.26 no.4
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• pp.8-19
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• 2021

In this study, the evaluation standard for nitrate nitrogen contamination degree (WELCUP) was established using six factors that influence the groundwater quality in Jeju Island. To do this, weightings, ranges, and ratings were assigned for each factor and the relative possibility of nitrate nitrogen contamination degree was evaluated using WELCUP index for each well. As a result of calculating the WELCUP index using groundwater quality data of 5,112 wells in Jeju Island for 27 years (1993-2019), all 61 wells with the WELCUP index value higher than 100 are distributed in Daejung and Hangyung watershed with relatively large area of farmland in Jeju Island. In particular, as the ratio of private wells is more than 64%, it is necessary that systematic management is needed for private wells in terms of nitrate nitrogen contamination. Consequently, based on the results of applying the WELCUP evaluation standard, it is necessary to select the prioritization of nitrate nitrogen contamination pathways project for groundwater wells in Jeju Island.

• Journal of Environmental Health Sciences
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• v.48 no.4
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• pp.227-235
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• 2022

Background: Abandoned metal mines are classified as vulnerable areas with the highest level of soil contamination among risk regions. People living near abandoned metal mines are at increased risk of exposure to toxic metals. Objectives: This study aimed to evaluate the correlation between soil contamination levels in areas around abandoned metal mine and the blood lead levels of local residents. Moreover, we assess the possibility of using soil contamination levels as a predictive indicator for human exposure level. Methods: Data from the Survey of Residents around Abandoned Metal Mines (2013~2017, n=4,421) and Investigation of Soil Pollution in Abandoned Metal Mines (2000~2011) were used. A random coefficient model was conducted for estimation of the lower level (micro data) of the local resident unit and the upper level (macro data) of the abandoned metal mine unit. Through a fitted model, the variation of blood lead levels among abandoned metal mines was confirmed and the effect of the operationally defined soil contamination level was estimated. Results: Among the total variation in blood lead levels, the variation between abandoned mines was 18.6%, and the variation determined by the upper-level factors such as soil contamination and water contamination was 8.1%, which was statistically significant respectively. There was also a statistically significant difference in the least square mean of blood lead concentration according to the level of soil contamination (p=0.047, low: 2.32 ㎍/dL, middle: 2.38 ㎍/dL, high: 2.59 ㎍/dL). Conclusions: The blood lead concentration of residents living near abandoned metal mines was significantly correlated with the level of soil contamination. Therefore, in biomonitoring for vulnerable areas, operationally defined soil contamination can be used as a predictor for human exposure level to hazardous substances and discrimination of high-risk abandoned metal mines.

• Journal of Digital Convergence
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• v.11 no.12
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• pp.665-672
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• 2013

In radiology department, where patients with a variety of diseases receive their tests, there is a large possibility of cross contamination of nosocomial infection. Magnetic resonance imaging (MRI) tests take particularly more time than other tests do, which increases the possibility of being exposed to cross contamination. Therefore, this research examines the status of MRI equipment sterilization and investigates the bacterial distribution on head coils, which have the most frequent contact with patients, patient fixation blocks, and bores, which are confined spaces. The status of MRI equipment disinfection was examined by a survey targeting 150 employees, and the distribution of bacteria was measured in ten medical facilities. The result of bacterial distribution tests on MRI equipment showed various bacteria, including Staphylococcus, Acinetobacter, Sphingomona, Pantoea agglomeranss, Micrococcus, Bacillus, Saprophyticus, Brevundimona, and Myroidesspecies. The result of examining the stat us of MRI room disinfection showed that the disinfections of the head coil, block, and bore were implemented well, and the largest proportion was carried out once a day in the morning. The time and implementation of disinfection by the disinfection manager showed that they were implemented well when the manager was the MRI room examiner. The disinfection after examining a patient using an appropriate disinfectant is mandatory to prevent cross contamination.

• Korean Journal of Pharmacognosy
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• v.38 no.3 s.150
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• pp.205-216
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• 2007

South Korea is the representative consumption country of herbal medicines and most of herbal medicines circulating in Korea have been importing from the developing countries of Southeast Asia such as China, Vietnam, Indonesia and so forth. Domestic hygiene and safety are continuously proposed because herbal medicines which are circulating have the possibility could remain contaminants or residues. Physicochemical contaminants such as heavy metals, persistent organic pollutants, radionucleosides, microbial toxins, biological contaminants such as microorganisms and animals, agrochemical residues such as pesticides, substances used for fumigation, antiviral agents, and solvent residues are classified as major contaminants and residues in herbal medicines from 2005 September WHO.$^{1)}$ Currently our administration have established a permission standard and the inspection criteria against the heavy metal, the residual pesticides and a residual sulfur dioxide. Furthermore our administration is continuously monitoring and conducting researches for the policies and their scientific ground against herbal medicines. But the appearances or discoveries of the harmful new species due to environmental and industrial developments are becoming social problems. Therefore it may be necessary to continuously consider and investigate regarding hereupon. Recently, the contamination of the mycotoxins against foods such as cereals, nuts and the powdered red pepper have developed and started became problematic issue, and possibility of contamination against the herbal medicine is proposed. And since populations who are using the herbal medicines very limited to several nations, recognition and researches about contamination of mycotoxins in herbal medicines are very insufficient. Therefore it will be need to more focus on the international regulation of quality control and safety for herbal medicines. Now on, we are going to introduce the importance, occurrence, characteristic properties, World-wide research trends and detoxification of aflatoxins, which is known as the most potent mutagen, carcinogen and teratogen mycotoxins.