• The Korean Journal of Physiology
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• v.23 no.1
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• pp.109-117
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• 1989

The changes in adenosine triphosphate (ATP), creatine phosphate (CP) and lactic acid (LA) contents of guinea pig hearts were studied during the cardioplegia and recovery phase. 1) ATP and CP contents in cardiac ventricular tissue were decreased during the cardioplegia, regardless of $Ca^{2+}$ concentration in the cardioplegic solutions, and CP contents were recovered with the reperfusion of normal Tyrode solution faster than those of ATP. And there were no significant differences in the recovery of CP contents with different concentration of $Ca^{2+}$ in the cardioplegic solutions tested, while the recovery of ATP contents was faster with 15 mM $K^{+}$, 0.1 mM $Ca^{2+}$ cardioplegic solutions. 2) LA contents were increased during the cardioplegia and decreased with the reperfusion of normal Tyrode solution. 3) The more recovery time (up to 3 hrs), the more CP contents were recovered with the reperfusion of normal Tyrode solution faster than those of ATP. And LA contents were decreased as the duration of recovery time. These results suggest that $Ca^{2+}$ and $K^{+}$ concentration in the cardioplegic solution is one of the major factors influencing the recovery of cardiac tissue from the cardioplegia.

• Korean Journal of Construction Engineering and Management
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• v.18 no.6
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• pp.26-37
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• 2017

Preliminary scheduling at the initial stage of planning phase is usually performed with limited information and details. Therefore, the reliability and accuracy of preliminary scheduling is affected by personal experiences and skills of the schedule planners, and it requires enormous managerial effort (or workload). Reusing of historical data of the similar projects is important for efficient preliminary scheduling. However, understanding the structure of historical data and applying them to a new project requires a great deal of experience and knowledge. In this context, this paper propose a framework and methodology for automated preliminary schedule generation based on historical database. The proposed methodology and framework enables to automatically generate CPM schedules for airport projects in the early planning stage in order to enhance the reliability and to reduce the workload by using structured knowledge and experience.

• Korean Chemical Engineering Research
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• v.54 no.3
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• pp.320-331
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• 2016

Linze-Donawitz gas (LDG) adjunctively produced in the steel mill contains over 60% of CO. Two processes that recover high purity CO from LDG were considered: COSORB and CO-Pressure swing adsorption (PSA). This study aimed to decide which one is more economically feasible than the other by techno-economic analysis (TEA). From the technical point of view of TEA, the process flow diagram (PFD) was constructed, the mass and energy balances were calculated, and the equipment type and size were determined in order to estimate the total capital investment (TCI) and the total production cost (TPC). From the economic point of view of TEA, economic performance such as return on investment (ROI) and payback period (PBP) was evaluated, and the sensitivity analysis was carried out to identify key factors influencing ROI and PBP. It was found that CO-PSA is more economically feasible due to higher ROI and lower PBP. The CO price highly influenced ROI and PBP.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.3
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• pp.485-492
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• 2017

This study was conducted to identify the preservice teacher's health perception and health promoting behavior, and attitudes towards children with asthma, as well as to examine the relationship between these variables and the influencing factors. The participants were 329 third and fourth grade students from the national university of education in G city. The data were analyzed using Pearson correlation coefficients, t-test, ANOVA, Scheffe test, and multiple regression with SPSS/WIN 23.0. The score for the participants' health perception was 2.85 out of a possible 4, health promoting behavior about 2.49 out of a possible 4, and their score for attitude towards asthma was 3.67 points of a possible 5. The health perception and health promoting behavior showed a positive correlation with the attitudes about child with asthma. Interpersonal relations and health perception and grade had a significant influence on the attitudes about child with asthma. These variables accounted for 12.2% of the attitudes about child with asthma. The results highlight the need for intervention strategies to enhance the health promoting behavior and health perception.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.11
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• pp.104-113
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• 2016

This study was conducted to describe the relationship and influencing factors among college life adaptation, academic self-efficacy, and department satisfaction of freshman nursing students. There were 345 345 nursing freshman between November 30 and December 4 who participated in this study. The mean score of the college life adaptation, academic self-efficacy, and department satisfaction was $2.91({\pm}0.52)$, $2.79({\pm}0.60)$, and $3.55({\pm}0.47)$. The college life adaptation related with male group (p=.004), entering motivation (p=.027), friendship satisfaction (p<.001), first semester grade (p=.005), and academic self-efficacy related with male group (p=.040), entering motivation (p=.047), desired work (p=.015), friendship satisfaction (p=.014), first semester grade(p<.001), and department satisfaction related with entering motivation (p=.004), friendship satisfaction (p<.001), and first semester grade (p=.002) all showed statistical significance. There was a significant positive correlation among college life adaptation, academic self-efficacy (r=.223, p<.001), and department satisfaction (r=.342, p<.001). A significant and positive correlation was found between academic self-efficacy and department satisfaction (r=.218, p<.001). Department satisfaction was largely influenced by the college life adaptation. The regression model explained 23.1% of college life adaptation. In conclusion, this study showed that college life adaptation of freshman nursing students was correlated with academic self-efficacy and department satisfaction. Moreover, to increase the college adaptation of nursing freshman, it is necessary to develop educational programs to improve academic self-efficacy and department satisfaction.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.12
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• pp.81-90
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• 2016

The objective of this study was to investigate the effect of an education method applying the flipped learning technique for college students. Both self-directed learning readiness and educational performance before and after applying the flipped learning were examined. After applying the flipped learning technique, teacher-student interaction, learning satisfaction, and learning motivation were identified. The correlation of each variable was examined after applying the flipped learning technique to investigate its influence on learning motivation. A total of 68 second-year nursing students enrolled in E University were analyzed. A difference between before and after applying the flipped learning was analyzed by the paired t-test; a correlation between the variables was analyzed via Pearson's correlation coefficient; and an influence on the dependent variable learning motivation was analyzed using the stepwise multiple regression analysis. The results showed that self-directed learning readiness increased before and after applying the flipped learning technique with statistical significance, and the difference of educational performance was not significant. After an education session applying the flipped learning technique, a learning motivation demonstrated a significantly positive correlation with self-directed learning readiness (r=0.33, p=.006), college student educational performance (r=0.51, p<.001), teacher-student interaction (r=0.72, p<.001), and learning satisfaction (r=0.79, p<.001). A significantly positive correlation was also observed between the other variables. Factors influencing learning motivation were learning satisfaction and teacher-student interaction. The explanatory power for learning motivation in the regression model considering these two variables was 71.3% (F=80.66, p<.001). Therefore, to enhance learning motivation in applying the flipped learning technique, it is necessary to increase learning satisfaction and to establish a strategy that further vitalizes the teacher-student interaction.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.5
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• pp.497-506
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• 2017

The purpose of this study was to investigate the effects of life stress, depression, and drinking motives on problem drinking among college students. The subjects were 249 college students and data were collected through a self-reported structured questionnaire from Nov to Dec 2016. Collected data were analyzed by descriptive statistics, ANOVA, Pearson's correlation, and stepwise multiple regression. The findings showed that drinking motives were the biggest factor influencing their problem drinking with coping, social, enhancement and conformity motives exerting special effects on it. As for correlations with problem drinking, interpersonal and ongoing task stress of life stress had positive correlations with problem drinking. Coping, social, enhancement, and conformity motives also had positive relations with problem drinking. Drinking motives had critical effects on the problem drinking of college students with coping, social, and enhancement motives strongly impacting on it. The findings necessitate examining the drinking motives of college students to make them choose to drink including negative emotions, social activities, and gatherings in order to prevent their problem drinking. These factors could explain 33% of the problem drinking. It is also required to develop methods for them to utilize resources other than drinking and run drinking education and temperance programs at the school level.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.5
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• pp.285-293
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• 2017

This study examined the causal relationship among job stress, fatigue, and job satisfaction, which affect the turnover intention of elderly nursing home care workers. Data were collected from Sep.15 to Sep. 30, 2014. Structured self-administered questionnaires were delivered and collected without the respondents' personal information. The subjects were 232 female care workers working in nursing homes in D city. The data were analyzed using the SPSSWIN 21.0 and AMOS 21.0 programs. Covariance structure analysis was performed to estimate the causal relationship between the variables affecting the turnover intention of care workers. The results of the analysis were as follows. The variables included in this study were fatigue, which comprised 4.9% of job stress. Job satisfaction explained 54.6% of job stress and fatigue. The turnover intention was 46.2% due to job stress, fatigue, and job satisfaction. In other words, job stress, fatigue, and job satisfaction had a direct or indirect effect on the turnover intention of care workers. In conclusion, job stress, fatigue, and job satisfaction affect the turnover intention. Therefore, a policy to improve the work environment and working conditions is needed to reduce the turnover intention of care workers, and fulfill their duties in a stable life time workplace.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.4
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• pp.395-402
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• 2018

This study was conducted to identify factors influencing subjective happiness among nursing students. Participants consisted of 147 nursing students who were in the third and fourth years at two universities located in the Chungbuk and Kyungbuk provinces. Data were collected using questionnaires that looked at college-based stress, clinical-based stress, self-esteem, and subjective happiness from September 26 to October 29, 2016. Collected data were analyzed using the SPSS 22.0 statistics program with descriptive statistics, an independent t-test, analysis of variance (ANOVA), Scheffe's test, and hierarchical regression. The mean score for subjective happiness was 19.91 (range: 4 to 28). The mean for college-based stress was 2.92, and clinical-based stress was 2.61 (range: 1 to 5). The mean for self-esteem was 29.74 (range: 10 to 40). The significant predictors of subjective happiness in nursing students were self-esteem (p<.001), economic status (p=.002), interpersonal relationships (p=.001), and satisfaction with their major (p=.003). The explanatory power of variance was 68%, with self-esteem serving as the major predictor variable for subjective happiness. Therefore, we need various strategies that can enhance self-esteem, satisfaction with the major, and interpersonal relationships in order to improve nursing students' subjective happiness.

• Proceedings of the KWS Conference
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• 2002.10a
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• pp.235-243
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• 2002

Ni-base superalloys are used extensively in industry, both in aeroengines and land based turbines. About 60% by weight of most modern gas turbine engine structural components are made of Ni-base superalloys. To satisfy practical demands, the efficiency of gas turbine engines has been steadily and systematically increased by design modifications to handle higher turbine inlet or firing temperatures. However, the increase in operating temperatures has lead to a decrease in the life of components and increase in costs of replacement. Moreover, around 80% of the large frame size industrial/utility gas turbines operating in the world today were installed in the mid-sixties to early seventies and are now 25 to 30 years old. Consequently, there are greater opportunities now to repair and refurbish the older models. Basically, there are two major factors influencing the weldability of the cast alloys: strain-age cracking and liquation cracking. Susceptibility to strain-age cracking is due to the total Ti plus AI content of the alloy; Liquation cracking is due either to the presence of low melting constituents or constitutional liquation of constituents. Though Rene 41 superalloy has 4.5wt.% total Ti and Al content and falls just below the safe limit proposed by Prager et al., controlled grain size and special heat treatments are needed to obtain crack-free welds. Varying heat treatments and filler materials were used in a laboratory study, then the actual welding of service parts was carried out to verity the possibility of crack-tree weld of components fabricated from Rene 41 superalloy. The microstructural observations indicated that there were two kinds of carbides in the FCC matrix. MC carbides were located along the grain boundaries, while M$_{23}$C$_{6}$ carbide was located both inter and intra granularly. Two kinds of filler materials, Rene 41 and Hastelloy X were used to gas tungsten arc weld a patch into the sheet metal, along with varying pre-weld heat treatments. The microstructure, hardness and tensile tests were determined. The service distressed parts were categorized into three classes: with large cracks, with medium cracks and with small or no visible cracks. No significant difference in microstructure among the specimens was observed. Specimens were cut from the corner and the straight edge of the patch repair, away from the corner. The only cracks present were found to be associated with inadequate surface preparation to remove oxidation. Guidelines for oxide removal and the welding procedures developed in the research enabled crack-free welds to be produced.d.