• Journal of Korean Society of Environmental Engineers
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• v.30 no.7
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• pp.705-711
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• 2008

In case of the domestic condition, as the initiating from Sumjin River Dam, total 14 units of multipurpose dams had been constructed in 1965 for the roles of flood control, waterpower generation, irrigation, water supply, industrial water supply. In the case of such multipurpose dam, it produces electric energy by converting the potential energy utilizing its head and quantity of the water into kinetic energy. However, in this process, since during the time when the turbine connected to the hydraulic turbine dynamo revolves and there occurs a loud noise, it brings the physical, mental bad influences to those people also a decline of an effective working efficiency. On such point of view, after selection of various 16 measurement points, this study has measured and analyzed the travelling characteristics of noise generated at the hydraulic turbine dynamo in Daechung Dam, and also has evaluated the degree of indoor noise using the evaluation index such as PSIL, NC. As the result of noise-evaluation, in case of Daechung Dam, since the noise damage grade appears very seriously at various spaces, it is considering that its soundproof measure would be necessitated keenly. Also, it is considered that such data could be utilized as the valuable material hereafter for establishment of an efficient noise-reduction countermeasure and a comfortable working environment for the hydraulic turbine dynamo plant.

• The Korean Journal of Pesticide Science
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• v.4 no.2
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• pp.1-10
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• 2000

Fungicide resistance study in Korea is still in its infancy, and most of those resistance studies are largely limited to newness of the detected resistant strains. In future, detection of fungicide-resistant strains has to be based on sensitivity distribution of pathogen populations to certain fungicides, and standard levels of certain fungicides for resistance should be determined under the basis of this data. Most of the early research on fungicide resistance in Korea has overlooked this point, and resulted in inconsistency and confusion for monitoring sensitivity shift of pathogen population among individual researchers. Fungicide resistance detected in vitro tests has to be documented in field trials by examining control efficacy against resistant and wild-type pathogen populations. Resistance detection in wife has to be correlated with lower activity in practice. Using this process, fungicide resistance will have a practical meaning. Fitness evaluation of resistant strains for survival is, in particular, of importance to determine the future stability of the resistance in the pathogen population. In fields, sensitivity change of pathogen populations should be carefully monitored with and without fungicide selection pressures to establish long-term management strategies against fungicide resistance. It is becoming an urgent task to provide information through research for designing and implementing successful counter-measures against fungicide resistance problems in Korea.

• Korean Journal of Human Ecology
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• v.17 no.1
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• pp.27-34
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• 2008

The purpose of this study is to study how college students cope with their stress and how the level of their self-differentiation affects degrees of stress and stress-coping strategies. The questionnaires were handed to 497 college students at Y university in Gyeongbuk Province and the data were analyzed in terms of Cronbach's ${\alpha}$-coefficient, frequency and percentage, t-test, and regression analysis by using the SPSS statistical package. The results of this study were as follows: 1. For stress level, degree of self-differentiation and stress coping strategies of the college students, the average scores were 3.56, 2.53 and 3.49, respectively in 5-point Likert Scale, indicating that the students possess the above-average score for the degree of self-differentiation and stress-coping strategies and the below-average score for stress levels. 2. From examination of difference verification of stress levels based on the degree of self-differentiation and effect of degree of self-differentiation on stress levels, it was found that the higher is the degree of self-differentiation the lower is the stress level. 3. From examination of difference verification of stress-coping strategies according to the degree of self-differentiation and effect of degree of self-differentiation levels on stress coping strategies, we found that the students of higher degree of self-differentiation exercise the more active stress coping strategies. These results show that the degree of students' self-differentiation is a significant variable that influences their stress levels and stress control methods. It is thought that students' self-differentiation functions to minimize their stress and to actively cope with their stressful situation and that a high degree of self-differentiation is a significant mediator variable that is beneficial to students' mental health. It follows from the above observations that while college students in this study seem to possess good degrees of self-differentiation and stress coping capabilities and low stress levels they need to seek for the ways to improve their degree of self-differentiation by seeing into themselves and relationships with others around them. Parents, schools and consultation agencies are required to take an active hand to educate and encourage them to cope with their stress positively.

• Proceedings of the Korean Institute of Resources Recycling Conference
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• 2005.10a
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• pp.34-46
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• 2005

For treating a huge amount of plastic waste with the environment problem, pyrolysis of plastic waste into alternative fuel oil is one of important issue in recycling methods. This study was introduced over the trend of generation of plastic waste, pyrolysis technology in domestic and foreign countries, basic technology in pyrolysis process and new technology of pyrolysis developed in KIER (Korea Institute of Energy Research). The characteristics of process developed in KIER are the continuous loading treatment of mixed plastic waste with an automatic control system, the minimization of wax production by circulation pyrolysis system in non-catalytic reactor, the reuse of gas produced and the oil recovery from sludge generated in pyrolysis plant, which have greatly the advantage economically and environmetally. The experiment result data in 300 ton/yr pilot plant showed about 81 wt% liquid yield for 3 days continuous reaction time, and also the boiling point distribution of light oil (LO) and heavy oil (HO) produced in distillation tower was a little higher than that of commercial gasoline and diesel, respectively.

• Geophysics and Geophysical Exploration
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• v.20 no.1
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• pp.43-48
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• 2017

The applicability of refraction survey has been tested using a wave glider widely used in long-term ocean observations around the world. To record seismic refractions, a single channel streamer with metal weight and a seismic recording system were mounted on the wave glider. We used GPS precise time synchronization signal and radio frequency (RF) communication to synchronize shot and recorder triggers and to control acquired data quality in real time. When the wave glider is positioned close to the set point, a 2,000 J sparker is exploded along the designed track at 2 second intervals. Through the test survey, we were able to successfully acquire refractions from the subsurface.

• Journal of Environmental Health Sciences
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• v.37 no.5
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• pp.376-386
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• 2011

Objectives: The aim of this study was to evaluate the microbial hazards posed by food utensils and fixtures in food service operations at selected middle and high schools located in Seoul, Korea. Methods: We collected 200 samples of utensils and fixtures including cups, spoons/chopsticks, food trays and tables from five different schools in Seoul. Target microorganisms of this study were divided into two groups: total bacterial count and total coliform as indicators of microbial contamination and Bacillus cereus and Staphylococcus aureus as pathogens of food poisoning. We used selective media to quantify microbial concentration and 16S rRNA PCR assay for qualitative analysis. In addition, intensive interviews with nutritionists were conducted and observations were made to identify factors that may affect microbial contamination. Logistic regression analysis was employed to examine the relationship between the microbial concentration and operation characteristics of each operation. Results: The level of microbial concentration in school B and C were significantly lower than in school A, D and E (p<0.05). Some samples from school A, D and E showed over 3.4 log CFU/100 $cm^2$ (total bacterial count) and 1.0 log CFU/100 $cm^2$ (total coliform), which requires immediate hygienic action. The number of customers per staff member, periodicity of hygiene education for staff and daily operation time of sterilizers were also found to be important factors related with the microbial contamination of food service operations. Conclusions: These results suggested that not only a HACCP (Hazard Analysis and Critical Control Point) approach, but also efforts to assess internal risk factors within operations be needed to reduce the microbial contamination of food utensils and fixtures. This study is expected to provide preliminary data for assessing microbial hazards in food service operations.

• Tuberculosis and Respiratory Diseases
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• v.75 no.6
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• pp.244-249
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• 2013

Background: Conventional biomarkers cannot always establish the cause of pleural effusions; thus, alternative tests permitting rapid and accurate diagnosis are required. The primary aim of this study is to assess the ability of pentraxin-3 (PTX3) in order to diagnose the cause of pleural effusion and compare its efficacy to that of other previously identified biomarkers. Methods: We studied 118 patients with pleural effusion, classified as transudates and exudates including malignant, tuberculous, and parapneumonic effusions (MPE, TPE, and PPE). The levels of PTX3, C-reactive protein (CRP), procalcitonin (PCT) and lactate in the pleural fluid were assessed. Results: The levels of pleural fluid PTX3 were significantly higher in patients with PPE than in those with MPE or TPE. PTX3 yielded the most favorable discriminating ability to predict PPE from MPE or TPE by providing the following: area under the curve, 0.74 (95% confidence interval, 0.63-0.84), sensitivity, 62.07%; and specificity, 81.08% with a cut-off point of 25.00 ng/mL. Conclusion: Our data suggests that PTX3 may allow improved differentiation of PPE from MPE or TPE compared to the previously identified biomarkers CRP and PCT.

• Journal of the Korean Ceramic Society
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• v.39 no.2
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• pp.184-189
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• 2002

This study, compared with data of PbO-base glass system is a part of new glass composition design with Bi-base composition for PDP Rib. As $Bi_2O_3-B_2O_3-ZnO$ glass composition including Bi, which have similar density value and work facility to PbO, properties of softening point, thermal expansion coefficient, chemical durability, dielectric constant, and structural changing by XPS were investigated. $Bi_2O_3-B_2O_3-ZnO$ glass system, added 50∼80 wt% $Bi_2O_3$ widely, were presented 400∼480$^{\circ}C$ softening temperature, $68{\sim}72{\times}10^{-7}/^{\circ}C$ thermal expansion coefficient and 13∼25 dielectric constant. These results were showed similar physical properties with Pb-base glass system of same composition content, application possibility as starting composition of rib material was identified through micro-control of components and physical properties. The bonding energy of $O_{1s}$ as the $Bi_2O_3$ content decreasing was increased and full width at half-maximum (FWHM) was decreased, which is caused by non-bridging oxygen increasing.

• Journal of the Korea Convergence Society
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• v.9 no.6
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• pp.77-88
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• 2018

"Standard Precautions" (SP) is important for nursing students as it will lead to the protection of health professionals from infectious diseases and prevention of the wide spread of epidemic illnesses. Therefore, this study investigated factors influencing nursing students' attitudes toward SP. Data were collected from 291 nursing students from May to June, in 2016. According to the results, perceived benefit (4.26) was the highest among sub factors of the health belief model, test score of SP was 78.8%, and attitude score (4 point scale) was 3.63. Perceived sensitivity, perceived benefits, perceived barriers, self-efficacy, knowledge about SP showed significant correlations with the attitudes towards SP. Among sub-factors of the health beliefs, perceived sensitivity (${\beta}=.152$, p<.05) and perceived barrier (${\beta}=-.125$, p<.05) were found to influence nursing students' attitudes toward SP (F= 5.680, p<.001). Hence, it can be concluded that a convergence education program promoting health belief is needed for improving attitudes toward SP among nursing students.

• Toxicological Research
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• v.26 no.4
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• pp.293-300
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• 2010

tert-Butyl acetate (TBAc) is an organic solvent, which is commonly used in architectural coatings and industrial solvents. It has recently been exempted from the definition of a volatile organic compound (VOC) by the Air Resources Board (ARB). Since the use of TBAc as a substitute for other VOCs has increased, thus its potential risk in humans has also increased. However, its inhalation toxicity data in the literature are very limited. Hence, inhalation exposure to TBAc was carried out to investigate its toxic effects in this study. Adult male rats were exposed to TBAc for 4 h for 1 day by using a nose-only inhalation exposure chamber (low dose, $2370\;mg/m^3$ (500 ppm); high dose, $9482\;mg/m^3$ (2000 ppm)). Shamtreated control rats were exposed to clean air in the inhalation chamber for the same period. The animals were killed at 2, 7, and 15 days after exposure. At each time point, body weight measurement, bronchoalveolar lavage fluid (BALF) analysis, histopathological examination, and biochemical assay were performed. No treatment-related abnormal effects were observed in any group according to time course. Based on those findings, the median lethal concentration ($LC_{50}$) of TBAc was over $9482\;mg/m^3$ in this study. According to the MSDS, the 4 h $LC_{50}$ for TBAc for rats is over $2230\;mg/m^3$. We suggested that this value is changed and these findings may be applied in the risk assessment of TBAc which could be beneficial in a sub-acute study.