• Journal of the Korean Society of Combustion
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• v.8 no.2
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• pp.1-6
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• 2003

Numerical simulations are conducted at atmospheric pressure in order to understand the effect of the oxygen enrichment level on structure of $CH_4/O_2/N_2$ premixed flames. Under several equivalence ratios the flame speeds are calculated and compared with those obtained from the experiments, the results of which are in good agreement. The effects of the oxygen enrichment are investigated on flames under fuel-rich conditions. As the oxygen enrichment level is increased from 0.21 to 1, the flame speed and the temperature are increased. The emission index of $CO_2$ is decreased in cases of flames for fuel rich mixtures, so the efficiency of combustion may be decreased. The maximum emission index of NO is obtained for 0.6 of the oxygen enrichment level.

• Journal of The Korean Association For Science Education
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• v.21 no.4
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• pp.677-688
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• 2001

The purposes of this study are to investigate the school science high achievers' achievements in enrichment physics, logical thinking level, and to analyze the relationship between logical thinking level and the achievement in enrichment physics of high achievers in science. The subjects were 357th and 8th graders who achieved highly in school science. To assess their achievements in enrichment physics, we developed a new test consisting of descriptive problems which were based on middle school curriculum. Those problems require one or two steps of thinking process, not simple knowledge of science. To assess logical thinking level, we used the instrument called GALT(Group Assessment of Logical Thinking) developed by Roadranka et al. The results showed that the school science high achievers' average achievement in enrichment physics was low, 56.3 out of 150, which indicated that they had not done much of enrichment learning beyond middle school science curriculum. Just only 54% of the school science high achievers are in formal logical thinking level. From the analysis of relationship between their logical thinking level and the achievement in enrichment physics, the value of the correlation coefficient was 0.174, which means that they are not almost correlated. Therefore, it is not desirable to judge science gifted children just from achievement in school science or enrichment physics, so both(logical thinking and the achievement in enrichment physics) tests should be taken for selecting gifted student.

• Journal of Gifted/Talented Education
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• v.7 no.2
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• pp.69-92
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• 1997

The purpose of the study was to evaluate the effects of the enrichment program for the gifted on gifted childrens development of the logical thinking and science process skills. The enrichment program consists of 200 enrichment courses in language arts, mathematics, sciences, social sciences and thinking for children at the age of 30 months to Grade 8. Enrichment programs are characterized as process-oriented, student-choice available, activities-oriented, open-ended, and interdisciplined. Subjects were 123 gifted children from Grade 1 to 3 at the Korean Academy of Gifted Education (KAGE), whose IQ scores were above 130 at their entry point to KAGE. Children were divided into two groups depending the duration of the program participation. Older Group participated in the program for longer than 13 months, while Newer Group did for shorter than 12 months. Mean of IQs of the two groups were not significantly different. They were tested on Logical Thinking Test and Integrated Process Skills Test revised by KEDI into Korean version in 1991. Descriptive statistics were calculated and group differences were analyzed with t-test, and scheffe test. The main finding were as follows: There were not significant differences between gender. Children in higher grades showed higher level of development. Older groups showed significantly higher level of logical thinking level of development. Older group showed significantly higher level of logical thinking and process skills than the Newer group inspite of the similar IQ levels to each other. The longer the gifted child participate in the enrichment program, the higher the development of childrens thinking skills.

• Korea Journal of Hospital Management
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• v.26 no.1
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• pp.26-41
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• 2021

Purpose: This study is to identify the relationship among married nurses' social support, work-family conflict and work-family enrichment and to examine the influence of social support on work-family conflict and work-family enrichment. Methods: Data were collected from married nurses working at three hospitals with more than 100 beds in J Province and analyzed by descriptive statistics, t-test, ANOVA, Mann-Whitney U test, Kruskal-Wallis H test, Pearson's correlation analysis and hierarchical regression analysis using SPSS 21 program. Findings: In the correlation analysis only social support and work-family enrichment showed positive correlation. As a result of hierarchical multiple regression analysis, social support still acted as a significant influence factor on work-family conflict and work-family enrichment even in the state of considering the effect of control variables. Conclusion: In order to lower work-family conflict and to enhance work-family enrichment of married nurses, it is necessary to introduce and implement welfare policies for work-family reconciliation at the workplace level and at home level it is necessary to provide concrete measures so that married nurses can find the value of life as workers while house working and nurturing.

• 한국연소학회:학술대회논문집
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• 2001.06a
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• pp.53-59
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• 2001

Experimental measurements are conducted to investigate the structure of flat $CH_4/O_2/N_2$ premixed flames. The flames are simulated using a detailed chemical kinetic mechanism. Four flames established at equivalence ratio = 0.55 are studied with the different $O_2$ enrichment level, ${\Omega}$ = 0.21, 0.25, 0.30, and 0.35. The measured flame speed and species composition profiles are compared with the calculations. Whereas there is overall good agreement between the measurements and predictions, it appears that as the $O_2$ enrichment level is increased the position of the flame is moved toward the exit of the burner and the rapid temperature rise happens near the exit of the burner, and some areas of further refinement in the kinetic mechanism are identified.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.26 no.4
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• pp.555-560
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• 2002

Numerical simulations of freely propagating flames burning stoichiometric CH$_4$/O$_2$/$N_2$mixtures are performed at atmospheric pressure in order to understand the effect of the $O_2$enrichment level on CH$_4$/Air flame. A chemical kinetic mechanism is employed, the adopted scheme involving 54 gas-phase species and 632 forward reactions. The calculated flame speeds are compared with the experiments for the flames established at several $O_2$enrichment level, the results of which is in excellent agreement. As a result of the increased $O_2$enrichment level from 0.21 to 1, the mole fraction of CO in the burred gas is increased. The flame speed and the temperature in the burned gas are also increased, but the thickness of the flame is severely shrunken in the preheat region. The maximum of the calculated EINO is obtained around 0.6 and 0.7 of the $O_2$enrichment level in cases of flames for fuel-lean mixtures.

• 한국연소학회:학술대회논문집
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• 2000.12a
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• pp.77-82
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• 2000

Numerical simulations of freely propagating flames burning stoichiometric $CH_4$/$O_2$/$N_2$ mixtures are performed at atmospheric pressure in order to understand the effect of the $O_2$ enrichment level on $CH_4$/Air flame. A chemical kinetic mechanism is employed, the adopted scheme involving 54 gas-phase species and 632 forward reactions. The calculated flame. speeds are compared with the experiments for the flames established at several $O_2$ enrichment level, the results of which is in excellent agreement. As a result of the increased $O_2$ enrichment level from 0.21 to 1, the mole fraction of CO in the burned gas is increased. The flame speed and the temperature in the burned gas are also increased, but the thickness of the flame is severely shrunken in the preheat region.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.29 no.2 s.233
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• pp.255-262
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• 2005

A comprehensive experimental and numerical study has been conducted to understand the influence of $CH_{3}Cl$ addition on $CH_4/O_2/N_2$ premixed flames under the oxygen enrichment. The laminar flame speeds of $CH_4/CH_{3}Cl/O_2/N_2$ premixed flames at room temperature and atmospheric pressure are experimentally measured using Bunsen nozzle flame technique, varying the amount of $CH_{3}Cl$ in the fuel, the equivalence ratio of the unburned mixture, and the level of the oxygen enrichment. The flame speeds predicted by a detailed chemical kinetic mechanism employed are found to be in excellent agreement with those deduced from experiments. Even though the molar amount of $CH_{3}Cl$ in a methane flame is increased, temperature at the postflame is not significantly varied, but the calculated heat release rate and emission index of NO are largely decreased for the oxygen enhanced flame. The function of $CH_{3}Cl$ as inhibitor on hydrocarbon flames becomes weakened as the level of the oxygen enrichment is increased from 0.21 to 0.5.

• Proceedings of the KSME Conference
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• 2004.11a
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• pp.1128-1133
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• 2004

A comprehensive experimental and numerical study has been conducted to understand the influence of $CH_{3}Cl$ addition on $CH_{4}/O_{2}/N_{2}$ premixed flames under the oxygen enrichment. The laminar flame speeds of $CH_{4}/CH_{3}Cl/O_{2}/N_{2}$ premixed flames at room temperature and atmospheric pressure are experimentally measured using Bunsen nozzle flame technique, varying the amount of $CH_{3}Cl$ in the fuel, the equivalence ratio of the unburned mixture, and the level of the oxygen enrichment. The flame speeds predicted by a detailed chemical kinetic mechanism employed are found to be in excellent agreement with those deduced from experiments. As $CH_{3}Cl$ addition is increased temperature at the postflame is not almost varied but the heat release rate and $EI_{NO}$ are decreased. The function of $CH_{3}Cl$ as inhibitor on hydrocarbon flames becomes weakened as the level of the oxygen enrichment is increased from 0.21 to 0.5.

• Journal of Korean Biological Nursing Science
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• v.18 no.4
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• pp.274-279
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• 2016

Purpose: Adolescents who experienced the alcohol consumption have gradually increased. Adolescence is a critical period of the neural plasticity in the brain. Neural plasticity is mediated by neurotrophins and has an impact on cognitive function. Environmental enrichment ameliorates the cognitive function and increases neurotrophins. Thus, we investigated the neuroprotective effect of environmental enrichment on ethanol induced cognitive impairment in adolescent rats. Methods: The ethanol groups and the controls groups were injected with ethanol (0.5g/kg) and phosphate buffered saline, respectively, through intraperitoneal from 28th day of birth for 11 days. The environmental enrichment groups were provided larger cages containing toys than the standard cage. Passive avoidance test and Y-maze test were performed to evaluate the spatial memory. Results: Environmental enrichment+ethanol group showed higher alterations than the standard environment+ethanol group in Y-maze test (p<.05). In hippocampus, The environmental enrichment+ethanol group showed significantly higher level of the number of c-fos positive celsl and density of tropomyosin receptors kinase B receptor than the standard environment+ethanol group (p<.05). Conclusion: So, we suggested that the environmental enrichment played a role as a prophylaxis for prevention of memory impairment induced by ethanol exposure in adolescence.