• Analytical Science and Technology
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• v.31 no.2
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• pp.96-105
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• 2018

This study aimed to improve the method for detecting eight secondary aliphatic amines (SAAs), so as to measure their concentrations in fresh water and tap water samples. NaOH (8 mL, 10 M) and benzenesulfonyl chloride (2 mL) were added to a water sample (200 mL), and the mixture was stirred at $80^{\circ}C$ for 30 min. An additional NaOH solution (10 mL) was added and the stirring was continued for another 30 min. The pH of the cooled mixture was adjusted to 5.5-6.0 by adding HCl (35 %), and the SAAs were extracted using dichloromethane (50 mL). This extraction was repeated once. The extract was then washed with $NaHCO_3$ (15 mL, 0.05 M) and dried over $Na_2SO_4$ (4 g). The extract was finally concentrated to 0.1 mL, of which $1{\mu}L$ was analyzed for SAAs by GC-MS. The linearity of the spike calibration curves was high ($r^2=0.9969-0.9996$). The detection limits of the method ranged from 0.01 to $0.20{\mu}g/L$, and its repeatability and reproducibility (expressed as relative standard deviation) were both less than 10 % (6.6-9.4 %). Its accuracy (measured in percentage error) ranged between 2.4 % and 6.1 %. The established method was applied to the analysis of five surface water and 82 tap water samples. Dimethylamine was the only SAA detected in all the water samples, and its average concentration was $0.79{\mu}g/L$ (range: $0.20-2.54{\mu}g/L$). Therefore, this study improved the analytical method for SAAs in surface water and tap water, and the regional and seasonal concentration distributions were obtained.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.20 no.2
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• pp.126-135
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• 1987

The physical properties, coliform groups, and nutrients were investigated to evaluate the sanitary Quality of the environmental water at Chinju area from May to October, 1986. The results were as follows : The pH ranged from 5.4 to 7.8 : water temperature ranged from 12.0 to $30.3^{\circ}C$ : electrical conductivity ranged from $0.51\times10^2\;to\;8.095\times10^2\mu\mho/cm$; chloride ion ranged from 3.6 to 126.8 mg/l, respectively. Especially, the concentration of the chloride ion at St.9 was 109mg/l which was higher than those of others. The $NO_3^--N$ ranged from 0.2336 to 14.1648 mg/l and the mean value was 5.4774 mg/l, the concentration of $NO_3^--N$ at St. 2 was higher as 40 times than that of St.4. The $PO_4^{3-}-P$ ranged from 0.0013 to 0.8315 mg/l, and the mean value was 0.0745 mg/l, the concentration of$PO_4^{3-}-P$ at St.8 was higher than that of others. The $SiO_2-Si$ ranged 1.7 to 15.28 mg/1 and the mean value was 5.81 mg/l. The value of St.8 and St.9 were higher than those of other stations but this value were lower $10\~13\;mg/l$ than the criterion for drinking water as 50 mg/l. The bacterial density of the spring waters ranged 9.1 to 4,600/100 ml (geometric mean : 205/100 ml) for total coliform 0 to 4s0/100 ml and 28.2/100 ml for fecal coliform. Composition of coliform was $38.2\%$ Escherichia coli, $25\%$ Entrobacter aerogenes, $13.2\%$ Citrobecter freundii and the others.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.4
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• pp.1534-1539
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• 2010

This study carried out dental checkup targeting 251 students in the 1st grade of S middle school and 220 students in the 1st grade of S high school in Seoul Metropolis. The results are as follows. As for the experience of dental hypersensitivity to oral symptoms in middle-and-high school students, 23.2% of high school students had experience of painful tooth when drinking or eating cold and hot beverage or food, compared to 14.3% of middle school students, and showed significant difference($\chi^2=6.08$, p<.05). As for the experience of painful teeth, 9.1% of high school students had experience of being sore, aching, and painful in the teeth, compared to 4.4% of middle school students, and showed significant difference($\chi^2=4.23$, p<.05). As a result of the oral health behavior in middle-and-high school students, 48.6% of middle school students were indicated to be higher than 26.4% of high school students in the experience of having ever gone to dentist for the past 1 year, and showed statistically significant difference($\chi^2=24.56$, p<.001). As for the period of toothbrushing during one day, 68.5% of middle school students brushed teeth after having breakfast($\chi^2=6.39$, p<.05) more than 57.3% of high school students. After having lunch, 16.8% of high school students brushed teeth more than 7.2% of middle school students, and showed statistically significant difference($\chi^2=10.58$, p<.01). As a result of judging dental checkup in middle-and-high school students, 44.1% of high school students had dental caries($\chi^2=25.36$, p<.001) more than 22.3% of middle school students. 9.6% of middle school students had tooth loss more than 4.1% of high school students, and showed statistically significant difference($\chi^2=5.39$, p<.05).

• Applied Biological Chemistry
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• v.44 no.2
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• pp.97-102
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• 2001

Cheju island depends on a hydrogeologically vulnerable aquifer system as its principle source of drinking water. Most of golf courses are located in the area which is important for the ground water recharge, and pesticides are applied to golf courses often at relatively high rates. Therefore, turf pesticides in golf course should be applied without adversely impacting ground water. In this experiment, downward movement of pesticides was monitored in model greens of golf course, where different adsorbents were layered in 3-cm thickness at 35-cm depth, and effect of the adsorption layer on the leaching loss of pesticides was investigated. Major leachings were observed in the periods of heavy rain and very limited leaching was observed under artificial irrigation. Fenitrothion and triadimefon, which have relatively short persistence and high adsorption coefficient, were found in the leachate in low concentrations only at the first rainfall event, around 20 days after the pesticide application. However, diniconazole, which has a relatively long half-life (97 days), was detected in the leachate during the whole period of experiment and concentration was much higher than those of the other pesticides. Maximum leachate concentrations were 1.9, 10.3, and 84.5 ${\mu}l^{-1}$ for fenitrothion, triadimefon, and diniconazole, respectively. Therefore, in golf course green which allows rapid water percolation and has extremely low adsorption capacity, persistence in soil could be more important factor in determination of leaching potential of pesticides. Total quantity of pesticides leached from the model green was <0.2% for fenitrothion and triadimefon and 1.8% for diniconazole. Adsorption layers significantly reduced pesticide leaching, and active carbon and Orpar were more effective than zeolite. In the model green having adsorption layer of active carbon or Orpar, leaching loss of pesticides was reduced below 0.01% of the initial application.

• Journal of Korean Society of Environmental Engineers
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• v.32 no.6
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• pp.639-648
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• 2010

The optimal conditions for the analysis of BPA by HPLC-MS/MS was investigated and the ultrasound degradation capacity of the BPA, with the goal to establish the proper directions for analyzing infinitesimal quantities of BPA by HPLC-MS/MS was examined. The MDL and LOQ of BPA analyzed by HPLC-MS/MS were measured 0.13 nM and 1.3 nM respectively, its sensitivity about 620 and 32 times greater than HPLC-UV (MDL: 81.1 nM, LOQ: 811 nM) and FLD (MDL: 4.6 nM, LOQ: 46 nM). In other words, the new method enables the analysis of BPA with the accuracy up to one 1,180th of the amount specified in U.S. EPA guideline for drinking water. Degradation rate of BPA by ultrasound measured over 95% under 580 kHz and 1000 kHz frequency within 30 minutes of treatment, whereas the rate showed some decrease at 28 kHz frequency. At 580 kHz of ultrasound has proven to be the most effective among others at degradation rate and $k_1$ value, so we concluded that this frequency of ultrasound creates hospitable condition for the combined process of degradation by pyrolysis and oxidization. With the addition of 0.01 mM of $CCl_4$, BPA with the initial concentration of 1 ${\mu}M$ was degraded by more than 98% within 30 minutes, the $k_1$ value measured 5 minutes and 30 minutes into the experiment both showed increases by 1.4 and 1.1 times, respectively, compared with BPA without $CCl_4$. It is also found that the main degradation mechanism of BPA by ultrasound is oxidization process by OH radical, based on the fact that the addition of 10 mM of t-BuOH decreased the rate of BPA degradation by around 60%. However, 33% of BPA degradation rate obtained with the addition of t-BuOH implies further degradation done by pyrolysis or other sorts of radical beside OH radical.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.8
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• pp.3958-3970
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• 2013

This study was carried out to grasp the job stress and intention to change their jobs of nurses at general hospitals by their socio-demographic, job-related and health-related behavior characteristics and especially to investigate their relationship to the job stress and intention to change their jobs. The subjects were 355 nurses working at three university hospitals located in Daejeon City, and data were collected by a survey using self-administered questionnaires structured from April 1 to May 31, 2012. As a results, the average point of the nurses' intention to change jobs by the causes for job stress was significantly higher in the boss group with low support than in that with high support while it was higher in colleague group with low support than in that with high support. To look into the correlation between the points of intention to change their jobs and the causes for job stress, their intention to change their jobs showed a significant negative correlation to the boss's support and colleagues' support while there was no significant relationship with job demands and job autonomy. As a result of hierarchical multiple regression, age, drinking coffee, department, job satisfaction, the boss's support and colleagues' support were selected as significant related variables affecting the nurses' intention to change their jobs and these variables' descriptive power was 29.4%. Viewed from the above results, it is suggested that the nurses' job stress and intention to change their jobs has a significant relationship with various variables such as socio-demographic, health-related behavior and job-related characteristics. In addition, there were a significant positive correlation between the causes for the job stress cause and intention to change their jobs, and among the causes for the job stress, support by their boss or colleagues turned out to be those affecting their intention to change their jobs. Thus, it is considered that it is necessary to minimize the nurses' job stress and at the same time to seek for specific measures for preventing their turnover.

• Journal of Nutrition and Health
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• v.51 no.2
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• pp.153-167
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• 2018

Purpose: This study was conducted to identify differences in dietary behaviors, dietary life consumer education related situation competencies, and dietary lifestyles between baby-boom and echo generations by gender. Methods: Data were drawn from the 2016 Food Consumption Behavior Survey, and 2,474 subjects (baby-boom generation 1,304; echo generation 1,170) were selected. Results: The baby-boom generation more frequently ate meals at home with family than the echo generation, whereas the echo generation had meals more frequently at cafeterias, cafes, bakeries, convenience stores and with friends or colleagues than the baby-boom generation. However, no significant differences in dietary life related consumer education were observed between generations, and experience with food related consumer education and food related promotional/events was very low in general. Baby-boomers received their primary dietary information from surrounding people, whereas the echo generation received it from broadcasting. The information use competence was lower for the baby-boom generation (3.29) than echo generation (3.35), although this difference was not significant. Healthy dietary life competence did not differ significantly, whereas the baby-boom generation showed a higher level of practice competence than the echo generation. Additionally, the baby-boom generation was more likely to pursuit health and less likely to be concerned with convenience and taste quality than the echo generation. Conclusion: The frequencies of meal eating places, drinking, and eating-out differed significantly between the two generations, while the participation ratios of food related consumer education/events, attitudes toward education, and information use competence did not. Additionally, knowledge regarding healthy dietary life competencies did not differ, whereas practice level showed significant differences between generations. Among dietary lifestyles, the baby-boom generation showed higher pursuit of health and lower pursuit of convenience and taste quality than the echo generation.

• Journal of the Korean Institute of Landscape Architecture
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• v.43 no.6
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• pp.62-72
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• 2015

The objective of this research is to investigate the different aspects in which users positively identify with indoor green walls and the influences that it has on usage behaviors. Under the hypothesis that public space users prefer locations with green walls, the effect on their behavior was observed. After installing indoor green walls, behavioral observations and questionnaires were carried out to analyze green wall preferences. The observation experiment was carried out for a total of 8 days in order to see what influences the preferences for of indoor green walls had on usage behaviors and compare a control group with an experimental group that experienced a green wall. The usage time data were put into an SPSS statistics program and used to run an independent sample t-test. The questionnaire was carried out for two days from March 1st to 2nd 2014 after the observation was completed, and was done by 224 users of the two areas. The results from the experiment are as follows. First, comparisons between the total usage time of seats adjoined to partitions in both the green walled area and the partitioned area showed that there was no preference for indoor green walls. Second, the results appeared to show a higher percentage of women users in the green walled area, compared to the original partitioned area. Third, it showed that partitions and plants did not have any influence on seat choices. Fourth, the questionnaire showed preferences for indoor green walls. Out of the 94 people who sat in the partitioned area, 11.7% answered that they wanted to sit in the green walled area, they couldn't due to the lack of available seats. Furthermore, out of the 130 people who sat in the green walled area, 24.6% said they chose the seat because of their preference for the green wall. Although 64.3% of users of the two areas said that they would choose the green walled area if under the same circumstances, the behavior observation did not reflect this.

• Journal of the Korean Institute of Landscape Architecture
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• v.43 no.6
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• pp.1-15
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• 2015

Changgyeongwon emerged as pleasure grounds following the creation of a museum, zoo and botanical garden in Changgyeonggung Palace during the Japanese colonial period. Pleasure grounds offer space for entertainment and have maintained the image of a paradise apart from reality. This study examined the creation process of pleasure grounds within a royal palace and the following spatial changes. By analyzing the image of Changgyeongwon as an artificial paradise, this study explored its landscape and cultural aspects. Literature reviews on the intention and process showed that the Changgyeongwon pleasure grounds were created as a 'royal garden' for the amusement of Sunjong, as well as 'public pleasure grounds' in the process of colonization. It was one of the first public spaces open to everyone who could afford the entrance fee. The layout of Changgyeongwon was studied by a comparison and analyzation of modern plans and photographs. It was composed of the central museum zone, northern botanical garden zone, and southern zoological garden zone. A conservatory and greenhouse to exhibit and maintain tropical plants were intensively built in the botanical garden zone while an aviary was created on the zoo pond. In the vicinity of the aviary a vivarium was constructed. Museum exhibition facilities included a main building as well as existing buildings, and a western flower garden was created between the buildings. Space for children including a playground and horse-riding course were created in the 1930's. The paradisiacal image and pleasure grounds culture of Changgyeongwon were studied as follows. Firstly, it shows that Changgyeongwon's paradisiacal image where rare animals and exotic plants were open to the public was promoted by the zoo and botanical garden. This led to the creation of new popular leisure activities such as flower appreciation and animal watching. Secondly, Changgyeongwon offered an urban leisure space, symbolizing the 'non-urban nature within the city' where the urban residents could escape from the daily routine. Thirdly, Changgyeongwon was known for its 'fantastic night landscape' by its night opening during the cherry blossom season. This cherry blossom viewing at night sadly degenerated by various shows and drinking, and as a result, an image of a deviant paradise was given to Changgyeongwon. Changgyeongwon contributed to creating a new space with its diverse facilities, and the public embraced the urban culture through experiences of pleasure and entertainment.

• Journal of Nutrition and Health
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• v.42 no.6
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• pp.523-535
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• 2009

The aim of this study was to examine and compare the eating habits and dietary intake patterns of people with or without allergy by the survey during August-September, 2008. The 131 subjects aged 10'-50' (AG = allergy group, n = 62; NG = non-allergy group, n = 69) participated in this study. The questionnaire included general characteristics, dietary habits, and food frequency. Income level tended to be higher in AG than in NG, and AG had more pets and flower pots than NG (p < 0.01). In AG, most affected area of allergy was the skin and the subjects in AG experienced the mixed symptoms and more than 2 types of allergy. Family history of allergy was highly related with allergy of the subjects (AG: 66.1%, NG: 33.9%). Both groups did not exercise regularly, but frequency of alcohol drinking in AG was significantly higher than in NG (p < 0.01). AG skipped meals and had snacking more often than NG (p < 0.05). Most favorite snacks in AG were instant foods, fast foods, cookies, and ice cream (p < 0.05). Therefore, AG tended to consume more allergy-related foods than NG. Highly-consumed allergy-related foods were egg, pork, walnut, onion, tuna, shellfish, and kiwi (p < 0.05). Therefore, nutrition education and guidance is needed to establish good eating habits, food intakes, and life style in people having allergy.