• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.37 no.5
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• pp.512-518
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• 2024

Titanium oxide (TiO₂), a representative photocatalyst, reacts to ultraviolet ray energy and has antibacterial, deodorizing, and antifouling properties using superhydrophilic properties, so it is widely used in various industrial fields such as environmental purification, building exterior walls, and road facilities. However, due to the nature of the photocatalyst, it reacts to ultraviolet rays known to be harmful to the human body, and is designed to react to natural light outdoors and to ultraviolet light sources inside a sealed device indoors, so indoor space is extremely limited. This study aims to develop spatial antibacterial technology for everyday living spaces by researching methods for antibacterial and deodorization by reacting titanium oxide (TiO₂)-based photocatalysts with the visible light range emitted from lighting devices in everyday spaces. Through the results of this study, it was verified through experiments that the photocatalyst exhibits antibacterial and deodorizing properties in response to lighting devices (LED, fluorescent lights, etc.) used in daily life. Based on the research results, we hope that various studies will be conducted to create a safer living environment by applying this technology to various fields such as large-scale complex facilities where an unspecified number of floating populations gather, airports, port waiting rooms, and public transportation.

• Archives of Plastic Surgery
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• v.38 no.1
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• pp.121-126
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• 2011

Purpose: Vaccum-assisted closure (VAC) has rapidly evolved into a widely accepted treatment of contaminated wounds, envenomations, infiltrations, and wound complications. This results in a sealed, moist environment where tissue is given the opportunity to survive as edema is removed and perfusion is increased. Many plastic surgeons now place a VAC device directly over the fasciotomy site at the time of the initial procedure. Large amounts of the fluid are withdrawn, and fasciotomies can be closed primarily sooner. This study was designed to observe the effect of VAC in preventing complications in snake bitten hands. Methods: In our study of three cases of snake bite, three of them underwent the VAC treatment & fasciotomy of the wound in the hand. This cases, the posterior compartment of the hand was bitten for a few days, releasing incisions were made of the posterior hand and 125 mmHg of continuous vacuum was applied to fasciomy incision site and the biting wound. The dressings were changed three times per week. Results: Our study examining the effects of applied vacuum in preventing snake bite wounds showed that the incidence of tissue necrosis and compartment syndrome was significantly lower for vacuum-treated wounds than for conservative wounds. Serum myoglobin, CK-MB, and CPK levels measured after fasciotomy incision were significantly decreased. We obtained satisfactory results from early dorsal fasciotomy, drainage of the edema with the VAC system, and then primary closure. The postoperative course was uneventful. Conclusion: Envenomation is a term implying that sufficient venom has been introduced into the body to cause either local signs at the site of the bite and/or systemic signs. Use of the vacuum-assisted closure device in snake bite can result in a decreased rate of tissue necrosis, lymphatic fluid collection, hemolytic fluid collection, and edema. Early fasciotomy of the dorsal hand and VAC apply is the alternative treatment of the snake bite.

• Tunnel and Underground Space
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• v.32 no.4
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• pp.272-284
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• 2022

This study conducted tunnel blasting to evaluate the blasting effect of a shear thickening fluid-based blasting stemming material and a sealed plug device under development. STF single stemming and STF stemming materials were combined with plugs to a tunnel blasting to which the SAV-Cut method was applied, and the advanced rate and fragmentation of tunnel blasting muck pile were compared when sand stemming was used. Tunnel advanced rate was evaluated using a 3D laser scanner. When the STF stemming material and STF stemming material with the plug were compared to the sand stemming material, it increased by 5.7 and 5.36%, respectively. As a result of evaluation of the fragmentation of tunnel blasting muck pile, it was the best when the STF stemming material was applied, and it decreased by about 61% compared to the case of sand stemming blasting. However, no significant improvement in blasting effect was observed with the application of plug devices.

• Journal of Korean Academy of Oral Health
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• v.42 no.4
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• pp.136-144
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• 2018

Objectives: The aim of this study is to analyze the differences in factors related to the incidence of dental caries between children in fluoridated and non-fluoridated areas and compared the DMFT and DMFS scores to confirm the effect of water fluoridation program (WFP) in Geoje and Changwon. Methods: The oral health examination and questionnaire survey were conducted in fluoridated and non-fluoridated areas. The number of surveyed children aged 8, 10, and 12 years in the fluoridated and non-fluoridated area of two cities was 1,524 and 1,383, respectively. Self-recorded questionnaires included self-perception of their own dental health, daily toothbrushing frequency, intake frequency of cariogenic sweet snacks and beverages, experience of gingival bleeding, experience of unmet dental treatment, and use of oral hygiene device except for toothbrush and toothpaste. The prevalence of caries and fissure-sealant status were surveyed. The logistic regression analysis was used to analyze the difference in children's self-rated oral health status between the fluoridated and non-fluoridated area. The mean number of sealed teeth and surfaces, marginal means of the DMFT and DMFS scores adjusted for the difference in the samples' sex distribution, and region were compared between the fluoridated and non-fluoridated areas. Results: In the fluoridated area, the experience rate of unmet dental treatments was higher among children aged 10 years, intake frequency of cariogenic sweet snacks and beverages were higher among the whole sample, and experience rate of professional fluoride application were lower than in the non-fluoridated area. The DMFT score for permanent dentition adjusted for differences in sex, region, and mean number of fissure-sealed teeth in the fluoridated area was significantly lower among whole samples and 8-, 10-, and 12-year-olds alone than in the non-fluoridated area. Conclusions: WFP can alleviate oral health inequality because it is effective in reducing the incidence of caries among children is disadvantaged demographic, socioeconomic, and cultural contexts.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.18 no.4
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• pp.436-441
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• 2009

An air filter is a device to remove dust from the air supplied to the automotive engine. A requirement for the optimum air filter is to improve the capability to remove particles from the air it takes in, that is the efficiency and amount of dust collection. By removing dust from the air, the air filter prevents the engine cylinder from wear, reduces ventilation resistance, and thus improves engine output and guarantees intake performance. In order to guarantee such air filter performance, it is very important to properly seal the air filter. For passenger cars made in Korea, the air filters are fabricated with steel caps as their frames are large and their engine capacity is big. Recently however, European countries and Japan started using urethane for manufacturing the air filter, so that all foreign-made cars now have urethane filters. The urethanes used for air filters are applied in two ways: One is to use soft urethane for both top and bottom of the air filter and the other is to use soft urethane for the top and hard urethane for the bottom. Each of these method has unique problems. In this study, hard urethane is used for both top and bottom of the filter in order to improve those problems and increase the sealing efficiency. Especially for the top, NBR (rubber mold) is pre-settled in tough urethane and then the urethane is solidified through foaming, which makes it possible to develop a solid and double-sealed filter.

• Journal of the Korean Solar Energy Society
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• v.23 no.3
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• pp.63-71
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• 2003

According to the recent report, the lighting energy consumption of commercial buildings reaches to $30%\sim40%$ of the total energy consumption. It is more than that of cooling & heating energy consumption and it is the major target of energy-saving policy. It is obvious that they are interested in natural lighting device such as Light-shelf for the purpose of raising the lighting energy-saving efficiency. In most of highly developed countries, a thorough study on Light-shelf makes it possible to propose a practical plan while at home there leaves much to be desired to study a guiding principle of optimum plan in spite of its efficiency based on experiments using scale4 model and analysis of simulation. Aiming at making an optimum plan of Light-shelf suitable for the domestic situation, this study is worked by experiments using light-shelf and analysis of variables using illumination program. The experiments is to analyse the efficiency of Light-shelf on condition of the sky and the analysis is to make the simulation using illumination program. This study is composed of 1) the analysis of light with some variables such as presence of light-shelf and degree of angle using 1/2 scaled model 2) making the simulation using Lightscape, illumination program, In brief, concerning presence of light-shelf, it causes little difference in its efficiency in the overcast sky, whereas it decreases an illuminance of window side and provides inner side with the light, which decreases the ratio of the maximum to the minimum inner illuminance and makes the inner of illuminance to range evenly in the clear sky. On degree of angle, as the daylight increases in proportion of degree of angle, the ratio of the maximum to the minimum inner illuminance decreases, which makes it possible to increase the proportion of inner daylight.

• The Journal of the Korea institute of electronic communication sciences
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• v.9 no.5
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• pp.617-624
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• 2014

Recently, photovoltaic inverter is received attention in photovoltaic with introduction of feed-in tariff. However, this inverter has problems such as inability to respond flexible at climate change due to its opening, and decrease of efficiency and lifetime due to its abnormal operation. To solve the problem, we desire to develop the eco-inverter which has a temperature control to respond easily on the change of temperature, and use the sealed structure not to affect the environment. In addition, we derive the optimal position of cooling system which is placed inside of inverter to minimize the power consumption, and proposed the effective measure to improve the efficient of inverter by deciding the number of cooling system.

• Journal of dental hygiene science
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• v.14 no.4
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• pp.461-467
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• 2014

The objective of this study was to evaluate the impact of the Q-ray view, a novel optical device on reliability of assessing a tooth status by dental hygiene students in the training for dental hygiene process. Twenty patients were enrolled in this study. Oral examinations were conducted by both seventeen third-year dental hygiene students and a trained faculty member. Traditional visual inspection was performed in phase I and then re-examined with Q-ray view in phase II. Restoration codes and lesion codes for each tooth were recorded separately according to the predefined criteria. As a measure of reliability, percent agreement and Cohen's kappa were determined. Agreements for each intraoral regions and types of lesion and restoration were calculated. Paired t-test and Pearson chi-square test for two proportions were used to compare mean Cohen's kappa and percent agreement at each phase. For the lesion code, mean kappa values of phase II for intraoral regions were significantly greater than that of phase I (p=0.017). For the both of the lesion code and restoration code, percent agreements of phase II for each types of lesion and restoration were significantly greater than that of phase II (p<0.001 and p<0.001, respectively). Especially difference of percent agreements between phase I and II for incipient caries, caries and fracture were significant for the lesion code (p=0.046, p<0.001, and p=0.029, respectively) and for not restored or sealed, tooth-colored restoration were significant for the restoration code (p<0.001 and p=0.011, respectively). The reliability of assessing a tooth status was improved when the Q-ray view used in dental hygiene student with beginner level of expertise. Q-ray view can be a promising device for conducting and educating the dental hygiene process better.

• Journal of the Korean Wood Science and Technology
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• v.34 no.4
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• pp.22-30
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• 2006

The volatile organic compound (VOC) Analyzer is a portable device to measure the four main aromatic hydrocarbon gases: toluene, ethylbenzene, xylene and styrene. With the VOC Analyzer, a semiconductor gas sensor eliminates the need for the carrier gas which is required for conventional gas chromatographs. In addition, since the semiconductor gas sensor is supersensitive to gas components, it is not necessary to use a conventional gas concentrator or other complicated equipment. Compared with other measurement methods, the VOC analyzer is useful for measuring toluene, ethylbenzene, xylene and styrene in wood-based panel because of its ease in obtaining field results and repeating the test. The VOC Analyzer primarily measures four VOC in the air. In this study, we designed a test method of VOC measurement for particle board. A specimen was sealed in 3L polyester bag, after 96hours we could measure maximum VOC emission level that is a stabilized VOC Value. For easy, fast and economic testing of TVOC emission from wood-based panel, we developed the test method with the VOC Analyzer. The VOC Analyzer is expected to gain widespread use in the manufacturing field where a quick and easy test for VOC emission from wood-based panel is required. Furthermore, the VOC Analyzer promises to become an easier, faster and more economic technique than the currently used standard methods.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.1
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• pp.369-377
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• 2013

This paper deals with the state of charge(SOC) and life cycle evaluation algorithm for lead-acid battery, which is essential factor of the electric vehicle(EV) and the stabilization of renewable energy in the smart grid. In order to perform the effective operation of the lead-acid battery, SOC and life cycle evaluation algorithm is required. Specific gravity with the change of electrolyte temperature inside battery case should be obtained to evaluate the SOC of lead-acid battery, however it is difficult to measure the electrolyte temperature of sealed type lead-acid battery. To overcome this problem, this paper proposes the equation of thermal transmission to compensate internal temperature of the lead-acid battery. Also, it is difficult to exactly evaluate the life cycle of battery, depending on the operation conditions of lead-acid battery such as charging and discharging state, self discharging rate and environmental issue. In order to solve the problem, this paper presents the concept for gravity accumulation of charge and discharge cycle, which is the value converted at $20^{\circ}C$. By using the proposed algorithm, this paper propose the test device based on the Labview software. The simulation results show that it is a practical tool for the maintenance of lead-acid battery in the field of industry.