• Journal of the Korean Applied Science and Technology
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• v.39 no.4
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• pp.535-541
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• 2022

The radical reaction position was calculated by varying the calculation level for ACEL and ANT, which are detected with the highest frequency and concentration in PAHs pollution sites. The results of each calculation level were compared and evaluated with the existing literature. HF, B3LYP, B3LYP-D, and MP2 were used as the method for each level used for calculation. Except for HF, the MK charge by B3LYP, B3LYP-D, and MP2 was consistent with the experimental results. It was found that the dispersion effect was negligible in the calculation of ACEL and ANT because the calculation results by the B3LYP and B3LYP-D methods were the same. In particular, it was found that the MK charge calculation result by MP2 agrees well with the product/PAH ratio obtained as a result of the experiment. Considering the calculation cost, it would be preferable to use B3LYP to predict the radical reaction site of ACEL and ANT. However, considering the product/PAH ratio, it takes more time to calculate, but it is judged that it is better to use the MP2.

• Journal of IKEEE
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• v.28 no.1
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• pp.104-109
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• 2024

In this research, we explored the influence of post-annealing atmospheres on the electrical properties of Ga₂O₃/SiC heterojunction diodes. We fabricated Ga₂O₃/SiC heterojunction diodes by RF sputtering and after the fabrication the post-annealing in various gas atmospheres was performed. We measured the changes in deep-level defects using Deep Level Transient Spectroscopy (DLTS) and we conducted an electrical characteristic of J-V measurement and Hall measurement to analyzed the effects of annealing atmosphere on Ga₂O₃/SiC heterojunction diode. In the N₂ annealed devices, the highest on-state current was measured as 3.06 × 10^-2 A/cm^2, and an increase in carrier concentration of 3.8 × 10¹⁴ cm^-3 was observed. This confirms that the variations in deep level defects due to the post-annealing atmosphere can influence the electrical properties.

• Journal of the Ergonomics Society of Korea
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• v.36 no.5
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• pp.601-607
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• 2017

Objective: A method to assess the risk level of agricultural works considering work posture and working time was suggested, and the method was applied to the major fruit crops. Background: It is not complete to analyze only work postures when assessing risk level of agricultural works. Method: $3{\times}3$ matrix was employed, in which the severity level was taken from the REBA method and exposure level was taken from the working time, using the criteria of caution zone/hazard zone. Results: Among the 5 major fruit crops(apple, pear, grape, peach, persimmon), the highest level of ergonomic risk was found in the apple and pear, while medium level was found in other 3 crops, mainly because the working time was less in the 3 crops. Conclusion: It was found that when assessing the overall ergonomic risk of agricultural works, work posture and working time should be considered at the same time. Application: The suggested method could be applied to other non-cyclic tasks.

• The Korean Journal of Emergency Medical Services
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• v.23 no.3
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• pp.17-27
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• 2019

Purpose: To provide legislative data for the amendment of Article 36 of the Emergency Medical Service Act on the qualifications of emergency medical technicians. Methods: The study was drafted based on the Emergency Medical Service Act; data on the emergency medical technicians (EMT) system and curriculum in Korea, United States. Japan, and Taiwan; and previous studies on the EMT system in Korea. Results: The length of education. work scope. amd role of level 1 EMTs vary significantly depending on the type of qualifications they have as emergency medical professionals, while the supply of level 1 EMTs has already reached a point of saturation. Accordingly, the current regulation on allowing level 2 EMTs with at least three years of experience to take the level 1 EMT test presents serious inequity for students just graduating from their emergency medical services program. It is also a factor that degrades the professionalism of level 1 EMTs. Conclusion: Article 36, paragraph 2. subparagraph 3 of the Emergency Medical Services Act pertaining to regulations on "EMTs who have worked as level 2 EMTs for at least 3 years" needs to be removed.

• The Transactions of the Korean Institute of Power Electronics
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• v.21 no.3
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• pp.191-199
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• 2016

Conventional two-level Zeta converters have drawbacks, such as high voltage stresses and high current ripples. To address these problems, a three-level Zeta converter that uses a couple inductor is proposed in this study. The proposed converter utilizes the three-level power switching circuit to reduce the voltage stresses and inductor current ripples. Compared with the conventional converter, the proposed converter can improve power efficiency and power density. A 500 W prototype circuit is used to verify the operation and performance of the proposed converter via experimental results.

• The Korean Journal of Community Living Science
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• v.19 no.1
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• pp.11-19
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• 2008

This study was made to provide basic materials required to develop the program for desirable change of eating behavior which might be regarded as the aim of nutrition education. In this study, the relationship between the factors known to be affecting eating behavior like nutrition knowledge and dietary self efficacy was examined with high grade elementary students in Gangwon Province. The results are as follows; First, positive relationship was observed with significant difference(p<0.001) in the relationships between eating behavior and dietary self efficacy(r=0.465), between nutrition knowledge level and eating behavior(r=0.216) and between nutrition knowledge level and dietary self efficacy(r=0.312). Second, the ratio explaining the effect of dietary self efficacy and nutrition knowledge on eating behavior was 22.3%, and it affected in the order of significance level such that dietary self efficacy(p<0.001) and nutrition knowledge level(p<0.05). Third, the level of desirable eating behavior was consistent with the level of nutrition knowledge. And the scores of nutrition knowledge were $28.97{\pm}4.66$ for 'poor' group, $30.01{\pm}3.85$ for 'normal' group, $31.13{\pm}3.94$ for 'good' group and $31.75{\pm}4.10$ for 'excellent' group. When the scores of eating behavior was considered in accordance with the level of nutrition knowledge, there was difference between the groups with poor and normal scores and the groups with good and excellent scores(p<0.001), however, there was no difference between poor and normal group, and between good and excellent group. Fourth, it was found that dietary self efficacy affected the eating behavior level by level. The eating behavior score was $23.82{\pm}5.25$ for the poor dietary self efficacy group, $26.88{\pm}4.00$ for the normal group, $30.27{\pm}3.66$ for the good group and $32.81{\pm}3.79$ for the excellent group. It showed that as the degree of dietary self efficacy increased the degree of eating behavior increased in all four groups (p<0.001).

• Health Policy and Management
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• v.22 no.1
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• pp.129-144
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• 2012

Purpose : The purpose of this study was to investigate the level of emotional labor and to identify affecting factors on emotional labor among one university hospital employees. Material and Method : This study was based on cross-sectional, self-administered, and Internet-based survey. The survey was conducted from Mar. 2 to Mar. 28. 2011. Total subjects were 812 employees working in one university hospital. Total response rate was 61.5%. Modified evaluation tool was used, which was originally developed by Morris and Feldman, to measure the level of emotional labor among hospital personnel. In order to identify the affecting factors on high level of emotional labor, we conducted logistic regression. The SPSS statistical software package was used to perform the statistical analysis. All statistical tests were 2-sided and a p-value<0.05 was considered statistically significant. Results : Average score of emotional labor was 3.06. Employees(3.39) who are working at the emergency department and hemodialysis room indicated the highest level of emotional labor, followed by wards(3.14), department of administration(3.14), department of ambulatory cares(3.06). The factors affecting on the high level of emotional labor were the highest level of schooling, types of department, and types of personality(p<0.05). Conclusion : The survey results showed that there was significant level of emotional labors among hospital employees. Therefore, the efforts to reduce the level of emotional labors are needed.

• Journal of Plant Biology
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• v.33 no.3
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• pp.197-202
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• 1990

Exogenously applied spermine, spermidine and putrescine caused a delay of senescence in fronds Lemna gibba G3 under continuous illumination. When the proximal half of a frond containing the meristematic“pockets”was removed, endogenous spermidine level in the distal half (half frond) increased initially to a miximal level, which was followed by a decline during a period of 10 days of incubation in light. No appreciable changes were observed with putrescine or spermine levels. Treatment of fronds with $\alpha$-difluromethylarginine (DFMA) resulted in both reduced level of spermidine and enhancement of chlorophyll loss in half fronds. $\alpha$-difluoromethylornithine (DFMO) was found to be virtually ineffective in either parameter. Results of experiments with ABA and kinetin indicate that there is a close correlation between the progress of senescence and spermidine level in Lemna fronds under illumination. It is suggested that endogenous level of spermidine is associated, at least in part, with frond senescence in this aquatic plant.

• Journal of Periodontal and Implant Science
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• v.25 no.2
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• pp.290-300
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• 1995

Tooth mobility is one of the most important clinical parameters in examination, diagnosis, prognosis and treatment planning procedure. In order to determine the differences of tooth mobility according to radiographical bone level, clinical root length, clinical crown/root ratio, and bleeding on probing, 90 male adults with periodontal disease and 10 male adults with periodontal health($25{\sim}45$ years old) were selected through clinical examinations including occlusal relationship, probing depth, attachment level, and bleeding on probing. On the mandibular anterior teeth, standard periapical radiographs were taken, and tooth mobility was measured by Periotest(Siemens Co., Germany). The radiographic bone level of individual tooth was evaluated as coronal 1/3, middle 1/3, and apical 1/3 to anatomical root length, and clinical crown length from incisal edge to bone level and clinical root length from bone level to root apex were measured with Boley gauge, and subsquently clinical crown/root ratio was calculated. The difference of tooth mobility(Periotest value) according to radiographical bone level, clinical root length, clinical crown/root ratio, and bleeding on probing was statistically analyzed by unpaired Student t-test. Tooth mobility was significantly higher in bleeding group than non-bleeding group on probing in the teeth radiographic bone level of middle 1/3, with clinical root length longer than 6mm, and with clinical crown/root ratio over 0.3(p<0.01). But there was no statistical difference in tooth mobility between bleeding group and non-bleeding group on probing in the teeth with radiographic bone level of apical 1/3, with short clinical root length less than 5mm, and with clinical crown/root ratio under 0.2(p>0.05). The results note that the tooth mobility depends on clinical root length, clinical crown/root ratio and gingival inflammation, and in the teeth with relatively good alveolar bone support gingival inflammation is one of the most important factors that affect tooth mobility.

• Journal of environmental and Sanitary engineering
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• v.24 no.2
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• pp.1-8
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• 2009

This study was conducted at a Terminal, a Parking Lot, an Underground shopping center, a Funeral hall and a Hospital waiting room of Cheon An area in August 2008 to examine the concentration level of HCHO(formaldehyde). The concentration level of the remodeled sites were $39.4\;{\pm}\;12.0\;{\mu}g/m^3$ in the terminal, $32.7\;{\pm}\;7.3\;{\mu}g/m^3$ in the parking, and $97.8\;{\pm}\;29.4\;{\mu}g/m^3$ in the underground shopping center. The underground shopping center had the highest level and followed by the terminal and the parking. On the contrary, the site remodeling had the level of $17.7\;{\pm}\;12.4\;{\mu}g/m^3$ in the funeral hall and $17.9\;{\pm}\;0.6\;{\mu}g/m^3$ in the hospital waiting room. The funeral hall had highest level than that of the hospital waiting room. Both the remodeled sites and the not remodeled site had concentration level of HCHO below the standard level, but it was higher in the remodeled sites. There were no relations among the HCHO, the temperature and the humidity in facilities of Cheon An area.