• Transactions of the Korean Society of Mechanical Engineers
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• v.17 no.6
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• pp.1556-1571
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• 1993

Nitrogen oxides ($NO_x$) are air pollutants which are generated from the combustion of fossil fuels. Stage combustion is an effective method to reduce $NO_x$ emissions. The effects of $NO_x$ reduction by stage combustion in a pilot scale combustor(6.6kW) have been investigated using propane gas flames laden with NH$_{3}$ as Fuel-N. The results in this study are follows; (1) $NO_x$ emissions are dependent on the reducing environment of fuel-rich zone regardless of total air ratio. The maximum $NO_x$ reduction is at the stoichiometric ratio of 0.8 to 0.9 in the reducing zone. (2) $NO_x$ reduction is maximum when burnout air is injected at the point where the oxygen in reducing zone is almost consumed. (3) $NO_x$ reduction is dependent upon the temperature of reducing zone with best effect above 950.deg. C in the reducing zone. (4) The fuel stage combustion is more effective to reduce $NO_x$ formation in the wide range of stoichiometric ratio than two stage combustion. (5) The results of this study could be utilized mainly in a design strategy for low $NO_x$ emission from the combustion of high fuel-nitrogen in energy sources ratio than as an indication of the absolute levels of $NO_x$ which can be achieved by stage combustion techniques in large scale facilities.

• Journal of Powder Materials
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• v.24 no.5
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• pp.364-369
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• 2017

Ceramic powder, such as MgO, is added as a binder to prepare the green compacts of molten salts of an electrolyte for a thermal battery. Despite the addition of a binder, when the thickness of the electrolyte decreases to improve the battery performance, the problem with the unintentional short circuit between the anode and cathode still remains. To improve the current powder molding method, a new type of electrolyte separator with porous MgO preforms is prepared and characteristics of the thermal battery are evaluated. A Spherical PMMA polymer powder is added as a pore-forming agent in the MgO powder, and an organic binder is used to prepare slurry appropriate for tape casting. A porous MgO preform with $300{\mu}m$ thickness is prepared through a binder burnout and sintering process. The particle size of the starting MgO powder has an effect, not on the porosity of the porous MgO preform, but on the battery characteristics. The porosity of the porous MgO preforms is controlled from 60 to 75% using a pore-forming agent. The batteries prepared using various porosities of preforms show a performance equal to or higher than that of the pellet-shaped battery prepared by the conventional powder molding method.

• Journal of Korean Academy of Rural Health Nursing
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• v.1 no.1
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• pp.40-48
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• 2006

Purpose: This study was done to identify the experience of stress and burn-out in caregivers of patients with senile dementia. Method: To evaluate the degree of stress and burn-out in caregivers of patients with senile dementia, 64 caregivers and matched to 64 patients with senile dementia at a Primary Health Care Post in South Kyung Sung Province were selected. The study was carried out from March 6 to March 30, 2001. Data on the degree of dementia in the patients was measured by the MMSE-K (Mini-Mental State Examination-Korea) and caregiver characteristics such as, sex, age, marital status, educational level, job, socioeconomic status, religion, number in family, relationship with patient, duration of care, and chronic disease in caregiver were collected by direct interview with a questionnaire. Results: Of 64 patients with senile dementia, 15.6% were classified as mild dementia (MMSE score 20-24) and 84.4%, as severe dementia. There were no significant characteristics of caregivers associated with the degree of stress and burn-out experience. The degree of burn-out in these caregivers of patients with severe dementia (mean value 94.3) was significantly higher than the 81.4 for those caring for patients with mild dementia (p<0.05). However, the degree of stress was not significantly related with the degree of dementia. The proportion experiencing severe burn-out (above score 4) was 54.7% in the physical domain, 90.6% in the emotional domain, and 73.4% in psychiatric domain, respectively. Conclusion: The above findings suggest that the degree of stress and burn-out experienced by caregivers of patients with senile dementia are high. Also the degree of burn-out experienced by in caregivers of patients with severe dementia was higher than for those caring for patients with mild dementia.

• Journal of Korean Academy of Nursing
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• v.47 no.3
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• pp.392-405
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• 2017

Purpose: This study aims to develop a self-reflection program for nurses who have experienced the death of pediatric patients in the intensive care unit and to evaluate its effectiveness. Methods: The self-reflection program was developed by means of the following four steps: establishment of the goal through investigation of an initial request, drawing up the program, preliminary research, and implementation and improvement of the program. The study employed a methodological triangulation to evaluate the effectiveness of the program. Participants were 38 nurses who had experienced the death of pediatric patients (experimental group=15, control group=23); they were recruited using convenience sampling. The self-reflection program was provided over 6 weeks (6 sessions). Data were collected from April to August, 2014 and analyzed using t-tests and content analysis. Results: The quantitative results showed that changes in personal growth (t=-6.33, p<.001) and burnout scores (z=-2.76, p=.005) were better in the experimental group compared to the control group. The qualitative results exhibited two themes, namely "personal growth" and "professional growth", and ten sub-themes. Conclusion: The self-reflection program developed by this study was effective in helping nurses who had experienced the death of pediatric patients to achieve personal growth through self-reflection, and it was confirmed that the program can be applied in a realistic clinical nursing setting. Furthermore, it can be recommended as an intervention program for clinical nurses.

• Journal of the Korean Society of Marine Environment & Safety
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• v.21 no.6
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• pp.721-728
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• 2015

Due to paradigm shift in administration, the field of police administration, like its civilian counterpart, is spending effort to improve customer-oriented civil complaint service system, and this is leading to a negative factor in service providers, emotional labor, among police officers. This study examines amount of emotional labor of maritime police officers, and verify the effects of emotional labor on exhaustion. Results show maritime police officers experience about the same amount of emotional labor as other public workers, and emotional labor has effects on work exhaustion. In other words, perception of incongruity of emotion has positive effects on exhaustion on cynical attitude. Attention to emotional expression has negative effects on decrease of job effectiveness. As such, if the problem of emotional labor is neglected, it leads to exhaustion and can become a significant obstacle to performance due to negative organizational influence. Also, it can lead to serious physical and mental problems on the individual level. Therefore, policy implementation to prevent this problem is necessary.

• Korean Journal of Materials Research
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• v.20 no.8
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• pp.401-407
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• 2010

We studied the influence of different types of metal electrodes on the performance of solution-processed zinc tin oxide (ZTO) thin-film transistors. The ZTO thin-film was obtained by spin-coating the sol-gel solution made from zinc acetate and tin acetate dissolved in 2-methoxyethanol. Various metals, Al, Au, Ag and Cu, were used to make contacts with the solution-deposited ZTO layers by selective deposition through a metal shadow mask. Contact resistance between the metal electrode and the semiconductor was obtained by a transmission line method (TLM). The device based on an Al electrode exhibited superior performance as compared to those based on other metals. Kelvin probe force microscopy (KPFM) allowed us to measure the work function of the oxide semiconductor to understand the variation of the device performance as a function of the types metal electrode. The solution-processed ZTO contained nanopores that resulted from the burnout of the organic species during the annealing. This different surface structure associated with the solution-processed ZTO gave a rise to a different work function value as compared to the vacuum-deposited counterpart. More oxygen could be adsorbed on the nanoporous solution-processed ZTO with large accessible surface areas, which increased its work function. This observation explained why the solution-processed ZTO makes an ohmic contact with the Al electrode.

• Journal of Korean Society of Forest Science
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• v.104 no.2
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• pp.294-299
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• 2015

This study was conducted to investigate the influence of a forest healing program on the level of job stress and the profile of mood states (POMS). 38 public servants who were in charge of social welfare in A city as well as 24 metal health care workers in C province participated in the forest healing programs. The data were collected by a pretest-posttest design. The data analysis showed that both job stress and POMS levels were significantly improved by the forest healing program. The therapeutic effects of forests are highly expected to be utilized for healing programs for job stress reduction and burnout prevention.

• Journal of Digital Convergence
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• v.18 no.1
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• pp.177-186
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• 2020

The purpose of this study was to identify the mediating effect of organizational citizenship behavior in relation between incivility and professional quality of life. The data collected from June 8, 2018 to June 29, 2018, and the questionnaire from 250 nurses at 3 general hospital in D city. The data were analyzed by t-test, ANOVA, Scheffe's test, Pearson's correlation, hierarchical analysis and Sobel test. Organizational citizenship behavior showed perfect mediating effect in the relationship between incivility experienced by nurses and compassion satisfaction, and partial mediating effect in the relationship between incivility experienced by nurses and burnout. The results indicate that it is necessary to develop strategies and applications to enhance organizational citizenship behavior for improved professional quality of life of a nurses who experience incivility.

• Progress in Superconductivity and Cryogenics
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• v.19 no.3
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• pp.44-48
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• 2017

Current lead is a device that connects the power supply and superconducting magnets. High temperature superconductor (HTS) has lower thermal conductivity and higher current density than normal metal. For these reasons, the heat load can be reduced by replacing the normal metal of the current lead with the HTS. Conventional HTS current lead has same cross-sectional area in the axial direction. However, this is over-designed at the cold-end (4.2 K) in terms of current. The heat load can be reduced by reducing this part because the heat load is proportional to the cross-sectional area. Therefore, in this paper, heat load was calculated from the heat diffusion equation of HTS current leads with uniform and non-uniform cross-sectional areas. The cross-sectional area of the warm-end (65K) is designed considering burnout time when cooling system failure occurs. In cold-end, Joule heat and heat load due to current conduction occurs at the same time, so the cross-sectional area where the sum of the two heat is minimum is obtained. As a result of simulation, current leads for KSTAR TF coils with uniform and non-uniform cross-sectional areas were designed, and it was confirmed that the non-uniform cross-sectional areas could further reduce the heat load.

• KEPCO Journal on Electric Power and Energy
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• v.1 no.1
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• pp.1-8
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• 2015

When the line and switchgear of the substation system are disconnected, ferro-resonance can occur. This happens even if the capacitive reactance and inductive reactance are not equal, which are not common resonance conditions. Resonance conditions vary depending on the busbar configuration environment. Although the damping resistance method applying the existing saturable reactor to cope with ferro-resonance has been successfully applied on site, there can be loss of normal function during long-term operation. The reason is because the rise in the operating frequency of saturable reactors means the saturation number is increased. Therefore, it can no longer function as saturable reactor since the resistor having inadequate capacity is burned out. To address this problem, in this paper, an EMTP-based simulation test was performed by designing and applying a dual reactor method, which adds an extended divergence reactor to the 1st side of the VT. The test result confirms that when the divergence reactor is inserted, the voltage and current values obtained at the 1st side and 2nd side of the VT as well as current values of divergence reactor part were stabilized from the transient phenomena and return to normal values. When compared with existing measures, although this method is similar in adding having a reactor added to a system regarding ferro-resonance, it has the advantage of being able to prevent ferro-resonance in advance since the reactor is added before the system is saturated. In addition, because it does not use damping resistance, it can extend the equipment life and stabilize its operation. Therefore, there are a lot of differences in terms of its operating characteristics and achivement of goal between the conventional method and new divergence reactor method.