• Journal of Mechanical Science and Technology
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• v.19 no.10
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• pp.1957-1963
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• 2005

In this study, external condensation heat transfer coefficients (HTCs) of six flammable refrigerants of propylene (RI270), propane (R290), isobutane (R600a), butane (R600), dimethylether (RE170), and HFC32 were measured at the vapor temperature of $39^{\circ}C$ on a 1023 fpm low fin and Turbo-C tubes. All data were taken under the heat flux of $32\~116\;and\;42\~142kW/m^2$ for the low fin and Turbo-C tubes respectively. Flammable refrigerants' data obtained on enhanced tubes showed a typical trend that external condensation HTCs decrease with increasing wall subcooling. HFC32 and DME showed up to $30\%$ higher HTCs than those of HCFC22 due to their excellent thermophysical properties. Propylene, propane, isobutane, and butane showed similar or lower HTCs than those of HCFC22. Beatty and Katz' correlation predicted the HTCs of the flammable refrigerants obtained on a low fin tube within a mean deviation of $7.3\%$. Turbo-C tube showed the best performance due to its 3 dimensional surface geometry for fast removal of condensate.

• International Commerce and Information Review
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• v.12 no.4
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• pp.151-170
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• 2010

The present study made an empirical analysis for investigating the competitiveness of technology trades in Korea. In particular, the study deduced the correlation between technology export and technology import using the variables of Gross Domestic Expenditure on R&D and Per capita industry value added Productivity and employed fixed effect model in panel linear regression model. It is found that the R&D expenditure of OECD countries made a significant effect on the technology import and the value-added labor productivity made a significant result on both technology export and import. Therefore, it showed that the technology trade in Korea made a sensitive response to labor productivity in OECD countries. By panel analysis, machine, construction, ICT, and service industry affect most on technology export in Korea for recent 5 years. For technology import, electric-electron, chemical, service, and construction industry have significant effects. This study contributed to understanding of industrial characteristics affecting technology trades in Korea and empirical analysis to show correlation between the factors affecting technology trade.

• Journal of Korea Foundry Society
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• v.34 no.5
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• pp.156-161
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• 2014

This study is focused on the effect of $Al_2Ca$ as a modifier on eutectic Si modification of A356 alloy. Microstructural observation was carried out for as-cast, as-solution treated and as-aged samples. Solution treatment and aging were performed for 2, 4, 6 and 10 hrs at $540^{\circ}C$ and $170^{\circ}C$, respectively. Although A356 alloy, which $Al_2Ca$ was added, has no significant difference in as-cast phases with normal A356 alloys, it shows much more modified eutectic Si, grain refinement and improved tensile property both in as-cast and as-heat treated conditions. TGA result shows that $Al_2Ca$ added A356 alloy has a certain improvement in oxidation resistance.

• Korean Journal of Occupational Health Nursing
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• v.28 no.4
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• pp.293-299
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• 2019

Purpose: This study aimed to identify the factors that affect the health promotion behaviors of shift workers. Methods: Using self-administered questionnaires, data were collected between August 13th and 31st, 2018. Descriptive statistics were computed, and t-test, analysis of variance, and correlational and multiple stepwise regression analyses were conducted using International Business Machines Corporation (IBM) Statistical Package for the Social Sciences (SPSS) version 22. Results: Health promotion behaviors were significantly and positively correlated with psychological well-being (r=.491, p<.001), fatigue (r=.170, p=.030), and self-efficacy (r=.520, p<.001). Psychological well-being (${\beta}=.249$, p=.014), fatigue (${\beta}=.179$, p=.007), and self-efficacy (${\beta}=.335$, p=.001) had significant effects on health promotion behaviors and together explained 31.7% of the variance. Conclusion: A systematic educational program that enhances psychological well-being should be developed and implemented to nurture health promotion behaviors among shift workers. Additionally, an intervention program that can enhance health promotion behaviors should be implemented to improve self-efficacy and prevent fatigue among shift workers.

• The Korean Journal of Emergency Medical Services
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• v.27 no.3
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• pp.101-111
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• 2023

Purpose: This study attempted to identify how academic self-efficacy, grit, and learned helplessness influence Academic delay behavior in college students and provide a foundation for reducing Academic delay behavior in college students. Methods: Data was collected from October 12, 2023 to October 30, 2023 using a structured questionnaire from 170 college students at a university in City D. The data was collected using a structured questionnaire. Results: Academic delay behaviors were significantly negatively correlated with academic self-efficacy (r=-.371, p<.001) and grit (r=-.562, p=.012), and significantly positively correlated with learned helplessness (r=.341, p<.001). Conclusion: Finally, In order to reduce academic delay behaviors among college students, it is necessary to actively utilize educational environments that promote academic achievement and grit, academic-related counseling programs, and learning environments that do not suffer from academic helplessness.

• Journal of Digital Convergence
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• v.13 no.11
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• pp.197-204
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• 2015

This study aims to identify the effects: quality of chest compressions, height and weight of pregnant women cardiac arrest while lying $30^{\circ}$ inclined to the left has on the quality of chest compressions administered by 119 EMT. For the purpose of this study, 62 members of 119 EMTs in M, N, S, Y cities and G cities of J province agreed to join in the test and the test was conducted from June 15 to 16 in 2015. Two mannequins (Resusci Anne$^{(R)}$) were used for the study and the chest compression process was recorded with the use of the Laerdal PC Skill Reporting System$^{(R)}$. As a result, it was discovered that for patients with a $30^{\circ}$ left inclination, who were below 170 cm in height and 65 kg in weight, the proper frequency and depth of compression were unsatisfactory. With this in mind, training programs and instruments that can improve the quality of chest compressions depending on a person's (patient's) height and weight should be developed.

• Biomedical Science Letters
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• v.26 no.3
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• pp.170-178
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• 2020

Mycobacterium tuberculosis (MTB) continues to be one of the main causative agents of tuberculosis (TB); moreover, the incidence of nontuberculous mycobacteria (NTM) infections has been rising gradually in both immunocompromised and immunocompetent patients. Precise and rapid detection and identification of MTB and NTM in respiratory specimens are thus important for MTB infection control. Molecular diagnostic methods based on the nucleic acid amplification test (NAAT) are known to be rapid, sensitive, and specific compared to the conventional acid-fast bacilli (AFB) smear and mycobacterial culture methods. In the present study, the clinical performances of three commercial molecular diagnostic assays, namely TB/NTM PCR (Biocore), MolecuTech Real MTB-ID^® (YD Diagnostics), and REBA Myco-ID^® (YD Diagnostics), were evaluated with a total of 92 respiratory specimens (22 AFB smear positives and 67 AFB smear negatives). The sensitivity and specificity of TB/NTM PCR were 100% and 75.81%, respectively. The corresponding values of MolecuTech Real MTB-ID^® and REBA Myco-ID^® were 56.52% and 90.32%, and 56.52% and 82.26%, respectively. TB/NTM PCR showed the highest sensitivity; however, the concordant rate was 10% compared with sequence analysis. Although MolecuTech Real MTB-ID^® showed lower sensitivity, its specificity was the highest among the three methods. REBA Myco-ID^® allowed accurate classification of NTM species; therefore, it was the most specific diagnostic method. Of the three PCR-based methods, MolecuTech Real MTB-ID^® showed the best performance. This method is expected to enable rapid and accurate identification of MTB and NTM.

• Korean journal of applied entomology
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• v.38 no.2
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• pp.117-121
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• 1999

Development and reproduction of the sycamore lace bug, Corythucha ciliata, were investigated under different temperature regimes. Duration of development from egg to pre-adult of the sycamore lace bug measured seven temperatures ranged from 54.0 days at 18$^{\circ}$C to 17.9 days at 33$^{\circ}$C. Development was not successful at 15$^{\circ}$C and 35$^{\circ}$C. Developmental zero point and total effective temperature for development of egg, nymphal, and complete development were 1 1 .O, 10.9, ll.l$^{\circ}$C and 150.3, 230.6, 376.1 degree-days, respectively. Longevities of adult females varied to temperature from 51.8 days at 18$^{\circ}$C to 17.2 days at 33$^{\circ}$C. The average fecundity per female was greater at 25$^{\circ}$C and 28$^{\circ}$C compared with at other temperatures. The intrinsic rate of natural increase (r,) and net reproduction rate (R,) were highest at 28$^{\circ}$C as 0.170 and 73.25, respectively. As a result, optimum ranges of temperature for C. ciliata growth were between 25$^{\circ}$C and 28$^{\circ}$C.

• Clean Technology
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• v.6 no.2
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• pp.113-119
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• 2000

Due to the toxicity of dioxin in the incinerator flue gas, it becomes a severe social problem. Activated carbon adsorption process is one of the methods for removing dioxin in the flue gas and was investigated its performance for removing hazardous organic compounds. Since dioxin is very hazardous material, 1,2-dichlorobenzene(o-DCB), one of the precursor material of dioxin, was used as adsorbate. The effects of air flow rate, pressure drop in the bag filter, operation temperature of bag filter, and kinds of adsorbents on the removal of o-DCB were measured and analysed. Experimental results showed that the operating temperature was recommended within the range of $140{\sim}170^{\circ}C$ considering the operating condition of incinerator. Also it was necessary to maintain the pressure drop of bag filter $120mmH_2O$ for enhancing the adsorption at the surface layer of activated carbon formed on the bag filter. The use of mixture of same amount of activated carbon and diatomite showed more than 90% removal of o-DCB and also reduced the consumption of activated carbon.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.9
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• pp.610-618
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• 2016

This study was conducted to investigate the level of moral sensitivity, critical thinking disposition and perceived ethical confidence, as well as to identify the factors influencing the perceived ethical confidence in nursing students. The study evaluated 170 nursing students in D Province from May 16-20, 2016. Data were analyzed using a t-test, one-way ANOVA, Pearson's correlation and multiple regression. The mean score of the perceived ethical confidence was $3.54({\pm}0.51)$, the moral sensitivity was $4.92({\pm}0.59)$ and the critical thinking disposition was $3.45({\pm}0.39)$. There were positive correlations between the perceived ethical confidence and moral sensitivity (r=0.410, p<0.001) and critical thinking disposition (r=0.523, p<0.001). The significant factors influencing the perceived ethical confidence were moral sensitivity and critical thinking disposition, which explained 33.2% of the variance in perceived ethical confidence. Based on these findings, programs and teaching methods that develop moral sensitivity and critical thinking disposition are necessary for college nursing students to promote perceived ethical confidence.