• Journal of the Optical Society of Korea
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• v.14 no.3
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• pp.266-276
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• 2010

In the present study, an optical system is proposed for maskless lithography using a digital micromirror device (DMD). The system consists of an illumination optical system, a DMD, and a projection lens system. The illumination optical system, developed for 95% uniformity, is composed of fly's eye lens plates, a 405 nm narrow band pass filter (NBPF), condensing lenses, a field lens and a 250W halogen lamp. The projection lens system, composed of 8 optical elements, is developed for 4 ${\mu}m$ resolution. The proposed system plays a role of an optical engine for PCB and/or FPD maskless lithography. Furthermore, many problems arising from the presence of masks in a conventional lithography system, such as expense and time in fabricating the masks, contamination by masks, disposal of masks, and the alignment of masks, may be solved by the proposed system. The proposed system is verified by lithography experiments which produce a line pattern with the resolution of 4 ${\mu}m$ line width.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.25 no.3
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• pp.245-253
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• 2015

Objectives: One aim of the study is to compare filtering facepiece masks for healthcare workers between Korea and other countries. The other is to emphasize the importance of fit testing for these masks using an analysis of previous research. Materials: An extensive literature review was performed by searching a number of websites and existing studies. Results: KF94 and KF99 masks certified by the Korean CDC are suitable for healthcare workers as filtering facepiece masks. The standards for these respirators are similar to FFP2 and FFP3 of EN 143 and 149. The performance, such as filtering efficiency, is almost the same between KP94 and N95. It was found that fit testing of respirators for healthcare workers was important to reduce infection risk. Conclusions: KF94 should be emphasized as filtering facepiece masks for healthcare workers rather than N95. Even though Korea has no fit testing regulations, implementing fit testing in healthcare settings is strongly recommended to decrease infection risk.

• Journal of the Korean Society of Clothing and Textiles
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• v.40 no.1
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• pp.114-130
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• 2016

This research provides practical data to develop UV protection masks and dust protection masks. It surveyed uncomfortable factors and significant characteristics for masks. It used 653 subjects 20-79 years old and performed the research from April to May in 2014. Wearing masks at outdoor activities is not widely popular yet, but golf players, mountaineers and old people were quite interested in masks. People mainly wore a basic shape mask, but main age group of each mask shape was different. People usually prioritized the protection function and comfort of wearing over design; however, women, young generation and people attending to outdoor activities longer than 1 hour considered design quite important. People going on picnic or camping consider mask characteristics most important. Therefore, various mask shapes and protective functions should be developed to reflect consumer needs. Meanwhile, the discomfort levels of masks were not too high, but old people felt more discomfort than young people. The most discomfort factors were 'other's eye', 'distracting face movement' and 'feeling of foreign object'. They also mentioned falling problem of C shape mask and short-rib shape mask, and asked for a 'tighter fit' at the ear.

• The Journal of Industrial Distribution & Business
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• v.14 no.5
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• pp.31-39
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• 2023

Purpose: As SARS-CoV-2, which was the main cause of the global pandemic, has repeatedly mutated in various forms, the threat of the virus has decreased considerably, and the spread has also subsided. Therefore, the purpose of this study was to explore the change in the role of masks and sustainable mask consumption according to the change in perception of wearing masks during the pandemic. Research design, data and methodology: This study used a descriptive review method as a literature review, and utilized the literature search method in PubMed, Riss, Scopus, and Google Scholar databases. Among them, a total of 46 papers were selected in the final stage. Results: As a result, it can be seen that during the pandemic, masks changed their roles according to social trends as their perceptions changed from general perceptions of protecting from external environments or diseases to fashion items with quarantine functions. Conclusions: Masks will be continuously consumed as one of the fashion items with the function of quarantine that protects the respiratory tract from the external environment that is indispensable in our daily lives. Therefore, measures should be taken on sustainable consumption measures according to consumer demand for disposable masks.

• Journal of Korea Multimedia Society
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• v.25 no.4
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• pp.610-619
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• 2022

Recently, the market for masks has been growing due to air pollution, sun protection, pollen allergies and other reasons. In addition, the demand for masks has increased dramatically due to the new coronavirus from 2020, and masks are still one of the necessities of life. Although the reliance on masks is increasing, there are many inconveniences associated with wearing masks for long periods of time. At the same time, technology is developing rapidly, and the demand for smart wearable devices is increasing. Therefore, at the moment when the fourth industrial revolution is underway, combining people's common necessities with IoT technology to bring new convenient experiences to people is an important direction for future technology development and product development. In this study, smart masks were designed and implemented using IoT(Internet of Things) technology. The mask uses a microcomputer Adafruit circuit playground express, using the microcomputer's LED, optical sensors, can be in the dark place light, and through the temperature sensor real-time grasp of body temperature changes. If the body temperature rises above normal, the LED will turn "on" and activate the voice sensor to warn yourself and others around you.

• (The) Research of the performance art and culture
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• no.33
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• pp.129-163
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• 2016

This study examines processes of cultural introductions and transformations among Korea, China and Japan via focuses on the formative characteristics of nasori(納曾利) masks belonging to komagaku (高麗樂), part of bugaku (舞樂), a Japanese court dance and music. Previous studies of traditional masks in East Asia focus on their dramatic characters and entertaining aspects. On the contrary, it approaches to their origins through the formative characteristics of komagaku nasori masks. Prince of Lanling, the representative togaku passed to Japan, and komagaku nasori perform a pair of toubu (答舞). One formative characteristic between Prince of Lanling and nasori masks is a dangling jaw (吊り顎). Masks having 'he' (へ)-shaped eyes like Japan's okina (翁) masks are characterized by a division (切顎) between the face and jaw, which is as same as the Korean masks. Other common grounds between Prince of Lanling and nasori masks are grotesque ghost faces and concentric double-circled eyes with their outlines painted gold. Concentric double-circled eyes prove that they spread to broader areas before the age of togaku and developed into a variety of divine-animal mask patterns. That Korean masks and nasori masks both have concentric double-circled eyes and dangling jaws is a significant starting point in studying the origin of traditional performing art in East Asia. Japan's bugaku has been passed down in shrines as part of folk religion. However, there exist in Korea no records or examples related to komagaku nasori masks introduced to Japan. This study provides some clues to comparison between Korean masks and komagaku nasori masks by focusing on the formative characteristics of the latter. The researcher suggests a new perspective to nasori mask dance by re-examining earlier Korean studies of the introduction of Daemyeonmu of Prince of Lanling to Japan through Shilla and the assumption of Nasori as Shilla music.

• Journal of Digital Convergence
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• v.19 no.2
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• pp.439-446
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• 2021

This study was to investigate whether there are differences in subjective bad breath-related characteristics and psychological characteristics of sports masks printed with natural minerals compared with quarantine masks and cotton masks. The study subjects were divided into 30 people in the Sports Mask Group, 30 people in the KF Mask Group (KMG), and 30 people in the cotton mask group (CMG), and a total of 90 subjects participated in the study. It was randomly sent to use 1 mask per day and 3 masks for 3 days. The study period was conducted from October 15, 2020 to October 30, 2020. As a result of the study, there was no difference in the use of masks between the three groups in terms of bad breath health and dry mouth. However, the sports mask was superior to other masks in oral respiration and bad breath angle. As a result of analyzing psychological factors, there was no difference between the 3 groups for depression. However, in the stress factor, sports masks were superior to other masks in stress. The results of this study are valuable as suggesting the direction of use of functional masks, and we hope that they will be used as basic data for functional mask research to be studied in the future.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.34 no.1
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• pp.48-56
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• 2024

Objectives: The coronavirus pandemic that began in 2019(COVID-19) has been one of the worst pandemics of the 21st century. Masks have been used to prevent COVID-19, but there are currently no standards for the long-term use of masks in the Republic of Korea. This study was conducted to assess the microbiological safety of KF94(Korea Filter 94) disposable face masks according to wearing duration by evaluating the bacterial filtration efficiencies of masks worn by research participants. Methods: A commercially available KF94 mask certified by the Ministry of Food and Drug Safety(MFDS) in the Republic of Korea was selected as the test mask. The research participants(n = 15) wore masks for the durations of one, three, and seven days. Participants also reported several parameters, including wearing time, makeup frequency, and storage. Bacterial filtration efficiencies of the worn masks were measured by a mask bioaerosol filtration tester. Staphylococcus aureus(S. aureus) was used as the test bacteria and quantitatively measured through the cultivation method. Then, bacterial filtration efficiency was calculated using the formula suggested by the MFDS. Results: All worn masks showed over 99.98% of mean bacterial filtration efficiency for S. aureus. There were no significant differences among bacterial filtration efficiencies of face masks according to wearing duration. There was also no significant difference among bacterial filtration efficiencies among participants. There was no correlation between the results of bacterial filtration efficiencies and reported parameters from participants. Conclusions: In the absence of significant external damage to the mask, the bacterial filtration efficiency of the mask can be maintained even after seven days of wearing. This result suggests that KF94 masks certified by the MFDS can be used repeatedly for about a week without loss of bacterial filtration efficiency.

• Journal of Environmental Health Sciences
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• v.46 no.1
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• pp.78-87
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• 2020

Objectives: To identify the degree of physical burden, a determination was undertaken of dust collection efficiency, inhalation pressure, and CO₂ concentration related to health masks certified by the Ministry of Food and Drug Safety (MFDS). Methods: Twenty health masks were purchased on the market. Dust collection efficiency and inhalation pressure were determined in the same manner as in MFDS certification testing, respectively using TSI Model 8130 (TSI, U.S.) and ART Plus (Korea). CO₂ concentrations for 20 subjects using a CO₂ analyzer (G100, G150, Geotechnical Instrument Ltd., UK) were measured with a similar method as a total inward leakage test. In addition to CO₂ levels, dead space volumes in the masks was determined for predicting concentrations of CO₂ in inhalation air. Results: Most of the dust collection efficiencies found for the 20 masks were far higher than the standard. Four KF94s met KF99 and four KF80s even met KF94. Most inhalation pressures were also much lower than the standard, with many almost one-half of the standard. The mean and standard deviation of CO₂ concentration in the mask were 2.9±0.44%. Considering dead volume, the prediction for CO₂ concentration in the inhalation air was 4,395±1,266 ppm. Conclusions: For healthy men and women, the dust collection efficiency and inhalation pressure of health masks were not at a level that would affect their health. Although CO₂ levels in the inhalation air were predicted not to affect health, research on the physiological effects of health masks on Koreans is needed for more precise research.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.9 no.1
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• pp.1-13
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• 1999

Even though there is no fit test regulations in Korea, in many developed countries, respirator fit testing is required before entering specific work environment to ensure that the respirator worn satisfies a minimum of fit and that the user knows when the respirator fits properly. Due to no regulation for fit test, a lot of Korean workers wearing respirators may be potentially exposed to hazards. Anthropometric test panels for testing the fit of respirators are very important to develop respirators fitted properly for Korean workers. To evaluate the fitting performance, 304 workers (272 males, 32 females) and 536 students (268 male, 268 females) were fit tested for 4 full-facepieces (2 domestic-made S, C, and 2 foreign-made T, N), 2 half masks (1 domestic-made S, and 1 foreign-made T) and 3 quarter masks (2 domestic-made S, C, and 1 foreign-made T) with PortaCount 8020. Fit factors of foreign-made masks were higher than those of domestic-made masks in all types. Males were fitted more properly than females. A facial dimension survey of 364 workers (339 males, 25 females) and 158 students (69 males, 89 females) was conducted to develop test panels for fit testing. Subjects were selected on the basis of face length and face width to wear full-facepiece masks in test. For testing half- and quarter masks, face length and lip length were used. Test panels containing 25 male-and-female subjects and 16 male subjects were respectively developed for full-facepiece, and half-and quarter masks to represent a majority of population surveyed.