• Applied Chemistry for Engineering
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• v.22 no.3
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• pp.249-254
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• 2011

A nonthermal plasma reactor in conjunction with a tubular type with a ferroelectric (high-dielectric ceramic) pellet layer was designed and constructed. $SrBiTaO_9$ (SBT) pellets with 2.0 mm in diameter were held within the tube arrangement by two metal mesh electrodes (20 mm separation) connected to a high-voltage AC power supply. The dielectric constant of SBT pellets was 150 at room temperature and 500 at curie temperature ($335^{\circ}C$). The generation rate of ozone in the plasma reactor almost linearly increased with increasing applied voltage. In the case of the plasma reactor packed with SBT pellets the generation rate of ozone sharply increased at the applied voltage more than 20 kV. The ozone generation rate at the negative corona discharge was higher than that of the positive corona discharge. However, the destruction efficiency of toluene and methylene chloride was not increased in proportion to ozone concentration.

• Transactions of the Korean Society of Automotive Engineers
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• v.9 no.6
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• pp.8-15
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• 2001

An aftertreatment system of diesel exhaust gas was attempted to extract particulate matters. The system consisted of a corona-less electrostatic precipitator to agglomerate soot particles and a counter-flow cyclone to collect them. When the effect of high voltage was examined at different configuration of electrode plates, the case of positive 15kV at both plates showed the maximum reduction of 38% in diesel smoke level. However, the back pressure became quite high as engine speed increased, so that minimizing pressure drop in cyclone should be studied with improving collection efficiency of soot particles.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1997.11a
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• pp.233-236
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• 1997

An investigation has been made of the various plasma chemistry reactions that occur in the corona discharge of an electrostatic precipitator operating in a typical flue gas. As the results of investigation, sulphur dioxide is removed principally by reactions with OH radicals to produce sulphuric acid, while nitrogen oxides are removed principally by reduction via the N radical to molecular nitrogen. If electrostatic precipitator\ulcorner used for flue gases are operated with positive voltages instead of negative dc voltages, there are significant reductions in the emission of the undesirable gases SO$_2$, NO, and NO$_2$. Thus, in this paper we design the bidirectional pulse generator for removal of flue gas, where the pulse width is more than 50[nsec] and the maximum output voltage is more than 100[kVl.

• Proceedings of the KIEE Conference
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• 2004.11a
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• pp.129-132
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• 2004

This paper presents an experimental study on the prebreakdown characteristics in $SF_6/N_2$ mixtures under non-uniform electric fields when subjected to the positive and negative lightning impulse voltages. $SF_6/N_2$ mixtures have a merit of an environmental aspect and cost reduction, and safty aspects. In order to analyze the prebreakdown processes in $SF_6/N_2$ mixtures stressed by impulse voltages, prebreakdown current and light were observed by a shunt with high sensitivity and a photo-multiplier tube, respectively. Additionally, characteristics of luminous events in flashovers were discussed.

• Journal of Naturopathy
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• v.10 no.2
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• pp.93-107
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• 2021

Background: The need for an investigation into the hygiene and awareness of hairdressers regarding Corona infection has emerged. Purpose: To investigate the level of interest in health and hygiene of hairdressers and their awareness of COVID-19. Methods: A questionnaire survey was conducted with hairdressers located in Daejeon Metropolitan City. The SPSS 26.0 program analyzed a total of 260 collected questionnaires. Results: The interest in the health and hygiene of hairdressers showed a statistically significant difference according to age, educational background, job title, type of hairdresser, and years of service. The hairdresser's risk and degree of awareness of COVID-19 were higher in those in their 30s or older, managers, medium-sized stores, and ten years of service. In terms of optimism about Corona, it was found to be high among those in their 20s, assistant staff, large stores, and less than five years of service. In addition, there was a positive (+) correlation between health care concerns, hand hygiene and mask hygiene, and awareness of corona risk and optimism. Conclusions: The level of health and hygiene interest and awareness of hairdressers significantly increased according to age, educational background, job title, type of hairdresser, and length of service. Therefore, it evaluated that this result would serve as primary data for research in this field.

• Journal of the Korean Applied Science and Technology
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• v.38 no.4
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• pp.963-973
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• 2021

Based on the TPB(Theory of Planned Behavior), this study explores the physical education perceived by college students by applying the causal relationship (SEM) to life sports, participation intention, and participation behavior perceived by college students in the Covid-19 environment, and to provide basic data for predicting life sports events. For this, a total of 267 people were analyzed using the mobile program "Survey Monkey" according to the sample plan from December 1, 2020 to May 1, 2020. As a result of the study, it was found that the planned behavior theory had a statistically significant positive(+) correlation with the intention to participate in physical education. The planned behavior theory showed that there was a statistically significant positive(+) correlation with the life sports participation behavior. Lastly, the intention to participate in physical sports was found to have a statistically significant positive(+) correlation with participation in physical sports.

• Clinical and Experimental Pediatrics
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• v.64 no.5
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• pp.239-246
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• 2021

Background: The consequences of severe acute respiratory syndrome corona virus 2 on mother and fetus remain unknown due to a lack of robust evidence from prospective studies. Purpose: This study evaluated the effect of coronavirus disease 2019 (COVID-19) on neonatal outcomes and the scope of vertical transmission. Methods: This ambispective observational study enrolled pregnant women with COVID-19 in North India from April 1 to August 31, 2020 to evaluate neonatal outcomes and the risk of vertical transmission. Results: A total of 44 neonates born to 41 COVID-19-positive mothers were evaluated. Among them, 28 patients (68.3%) (2 sets of twins) were delivered within 7 days of testing positive for COVID-19, 23 patients (56%) (2 sets of twins) were delivered by cesarean section; 13 newborns (29.5%) had low birth weight; 7 (15.9%) were preterm; and 6 (13.6%) required neonatal intensive care unit admission, reflecting an increased incidence of cesarean delivery and low birth weight but zero neonatal mortality. Samples of cord blood, placental membrane, vaginal fluid, amniotic fluid, peritoneal fluid (in case of cesarean section), and breast milk for COVID-19 reverse transcription-polymerase chain reaction tested negative in 22 prospective delivery cases. Nasopharyngeal swabs of 2 newborns tested positive for COVID-19: one at 24 hours and the other on day 4 of life. In the former case, biological samples were not collected as the mother was asymptomatic and her COVID-19 report was available postdelivery; hence, the source of infection remained inconclusive. In the latter case, all samples tested negative, ruling out the possibility of vertical transmission. All neonates remained asymptomatic on follow-up. Conclusion: COVID-19 does not have direct adverse effects on the fetus per se. The possibility of vertical transmission is almost negligible, although results from larger trials are required to confirm our findings.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.23 no.3
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• pp.1-11
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• 2023

With the development of information and communication technology, the size of the online market is increasing, and with it, the mobile shopping market utilizing smartphones is also growing day by day. This indicates that the effective use of mobile apps can be a strategic choice for businesses, and this is also true in the tourism and travel industry. In particular, the continuous growth of the OTA (Online Travel Agency) industry based on platforms has accelerated with With Corona, and due to its importance, this study aims to investigate the impact of perceived quality factors of mobile accommodation apps on reuse intention through emotional responses. To test the hypotheses, 260 users of mobile accommodation apps were analyzed, and the results showed that information quality has a positive impact on pleasure and dominance, and service quality has a positive impact on arousal and dominance, and pleasure and dominance have a positive impact on reuse intention. Through these findings, this study clarifies the relationship between mobile accommodation app quality factors and reuse intention, and effective marketing strategies were suggested by providing basic data for improving app quality.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.59 no.9
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• pp.1632-1637
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• 2010

A micro-water-nozzle, as one of a cooling means of micro-electronic devices, has been proposed and investigated. The I-V characteristics of the micro-water-nozzle and effect of applied voltage on the meniscus formation and deformation and ejection processes of de-ionized water on the micro-water-nozzle tip have been investigated. The water ejection processes, such as a drop formation, a drop deformation, a dripping, a cone jet, and an atomization, were taken place on the micro-water-nozzle tip by the electrohydrodynamic forces acted by the DC and AC high voltages applied on the meniscus of the micro-water-nozzle tip. The I-V characteristics of the micro-water-nozzle-to-plate electrode system were different from that of the same metal-point electrode system, due to the meniscus formation and water droplet ejection at the nozzle tip. The positive and negative DC and AC high voltages showed the water droplets ejection, the ejection rates of 1.8, 1.5 and 1.2 g/h respectively, which, however, showed that the proposed micro-water-nozzle-to-plate electrode system could be used as one of an effective pumping means.

• Journal of the Korean Society of Safety
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• v.23 no.4
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• pp.42-46
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• 2008

Ionizers are essential in various areas of manufacturing industries to protect electrostatic hazards and to reduce inferior products. For ion sources used in the charge neutralizers, there are corona discharge, soft X-ray, ultraviolet and glow discharge. Glow discharge has lots of attractive properties, such as lower discharge sustaining voltage, no generation of ozone, and so on. In this paper, we did an experimental study to trace the mechanism and stabilization of atmospheric pressure glow discharge using the several size and shape of electrodes. As an experimental result, to sustain conditions of atmospheric pressure glow discharge is that discharge voltage is 360V, discharge current is 12mA, apply frequency is 1kHz between electrodes when positive electrode is molybdenum(Mo) and negative electrode is copper(Cu). We confirmed that the mechanism and stabilization of atmospheric glow discharge is deeply concerned with the shape and material of electrode for discharge. Especially, glow discharge in atmospheric pressure was well generated and sustained according with the physical properties used electrode materials, example melting point, thermal conductivity, and etc.