• 한국컴퓨터정보학회논문지
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• 제27권10호
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• pp.185-193
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• 2022

본 연구는 성인 여성의 얼굴 유형에 적합한 마스크 패턴 개발을 위하여 시판되고 있는 다회용 마스크 패턴을 비교·분석하고자 하였다. 이를 통해 마스크 패턴 개발 및 생산업체에 필요한 자료를 제공하고자 하였다. 시판 다회용 마스크 패턴의 치수 및 형태를 비교한 결과, 성인용으로 제작된 L사이즈 마스크임에도 불구하고 치수에 있어서 큰 차이를 나타냈다. 가상착의에 대한 외관평가 결과 정면의 앞중심선의 수직, 마스크의 윗부분 감쌈과 여유, 코높이, 마스크 아랫부분의 감쌈과 여유에서 디자인별로 유의미한 차이가 있었다. 측면도 얼굴 옆부분의 감쌈, 옆부분의 여유, 끈 간격과 길이에서 유의미한 차이를 나타냈다. 외관평가 결과, 마스크4가 가장 좋은 평가를 받았다. 마스크 패턴의 형태는 코 아랫부분에 크게 다트가 있어 얼굴의 입체적인 형태를 커버할 수 있도록 되어 있으나 마스크에 따라 곡선의 정도와 각도에 차이를 나타냈다. 마스크 상부와 마스크 하부, 볼 부분은 밀착되지만, 코와 입 부분에는 여유가 있는 마스크 패턴의 평가가 높았다. 마스크 패턴은 얼굴형 및 치수에 대한 분석을 통해 마스크 상부길이와 하부길이, 코 높이에 따른 마스크 다트량의 설정이 이루어져야 할 것으로 생각된다.

• 한국의류학회지
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• 제48권3호
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• pp.417-432
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• 2024

This study aimed to enhance the comfort of health masks by conducting in-depth interviews, online surveys, and wearing tests on commercial health masks. The findings are summarized below. In-depth interviews revealed that the most comfortable mask styles were ranked as follows: Beak-1 (B-1) & Beak-2 (B-2) style > Flat style > 3-Horizontal foldable (3H) style. Men generally preferred flat style masks, while women favored beak-shaped masks. The internet survey results showed that 77.8% of surveyed brands offered a variety of mask styles, with 3H and B-2 masks being the most common. Different brands provided masks with different filtration levels, ranging from KF-AD to KF94. Size consistency also varied among brands, with flat masks having relatively consistent dimensions and B-2 masks showing significant size differences. Wearing tests indicated that 3H and B-1 masks were highly satisfying for categories like "itchiness," "unpleasant odor," and "mask slipping." Conversely, flat masks scored the highest satisfaction in classifications such as "stiff," "heavy," "thick," "hot while wearing it," "moisture accumulation," "breathing discomfort," "short ear straps," and "itchiness". Overall, the flat style, B-1, and B-2 yielded higher satisfaction levels, while 4-Horizontal foldable (4H) and 3H garnered lower satisfaction scores on wearing tests.

• 동굴
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• 제77호
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• pp.21-30
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• 2007

Photo-lithography lies in the middle of the wafer fabrication process. It is often considered as the most critical step in the IC process. We use a mask in exposure steps of the photo-lithography. Typically, 20 to 25 different levels of masks are required to complete an IC device. That means, if a photo process can be developed with the use of only one photo mask, we can reduce more process cost. To satisfy this, we plan to develop an alternative photo mask. For this reason, we chose to use a LCD. We expect to develop a LCD panel that can be changed by electrical control. This is the main idea about the adjustive photo mask. The Photo mask made of LCD panel will replace the former one.

• 제어로봇시스템학회논문지
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• 제14권4호
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• pp.348-352
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• 2008

Deformation of the shadow mask is one of the problems encountered during the deposition of organic materials for manufacturing large size organic light emitting diode (OLED). The larger the glass substrate, the larger the shadow mask becomes. As the size of the shadow mask increases, its deformation becomes more severe, thereby making it difficult to deposit organic materials in a precise pattern on a substrate. In this paper, a new method for reducing drooping of the shadow mask for large size OLED vapor depositions is proposed. The proposed shadow mask with cross stripe wires has higher stiffness than the pure shadow mask, which results in reducing drooping of the shadow mask. A commercial FEM program, ANSYS, is used for the evaluation of the proposed shadow mask. The analysis showed that the shadow mask with cross stripe wires have an effect on reducing drooping about 18.6% or more.

• 한국의류학회지
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• 제44권6호
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• pp.1163-1177
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• 2020

The purpose of this study is to figure out the information needed to improve the shape and size suitability of face-applied mask sheets. The study analyzed the shape of the mask sheet from the scanned images of 50 products of 37 domestic brands. In addition, each measurement of 42 mask sheets were compared and analyzed multilaterally with the 3D measurement dimensions of the faces of men and women in their 20s from the 6th SizeKorea data. Analysis on the shapes of mask sheets indicated that domestic commercial mask sheets are mainly made of single or dual sheets, with slits for enhancing fitness to the three-dimensional face. In the dimensional analysis of Korean men, women and mask sheets, most of the lengths of the mask sheets were significantly larger or smaller than the actual faces of men and women. The horizontal length and vertical length of the forehead above the eyes are significantly shorter, thereby requiring adjustments in the dimensions of this area. In order to improve the size suitability of the mask, it is necessary to adjust the dimensions of the problem area according to the research results as well as diversify the dimensions considering the target layer.

• 한국환경보건학회지
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• 제47권3호
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• pp.292-301
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• 2021

Objectives: Wearing medical masks has been recommended since the declaration of coronavirus disease-19 (COVID-19) as a pandemic disease. Certified medical masks are evaluated according to filtration efficiency and facial inhalation resistance. However, some people use non-certified common masks. This study aimed to evaluate various non-certified commercial masks based on the certification criteria for medical masks. Methods: Twenty mask products (three anti-droplet, three disposable dental, eight fashion, three cotton, and three children's masks) were selected. For performance evaluation, filtration efficiency and facial inhalation resistance tests were conducted. The evaluation method followed the certification method for KF-certified masks of the Ministry of Food and Drug Safety (MFDS) and the N95 respirator of the National Institute for Occupational Safety and Health (NIOSH). Results: None of the 20 masks met the KF94 certification standard set by the MFDS. Four and three masks respectively met the KF80 certification standard and the N95 standard of NIOSH. Filtration efficiency was significantly higher in three-layer masks than in single layer masks. Pleated-type masks had higher filtration efficiency than cone-type masks. There was no correlation between the structure of masks and facial inhalation resistance. Conclusion: While no masks complied with the KF94 certification standard, a few masks met the KF80 and the N95 certification standards of NIOSH. Although some people wear non-certified commercial masks, protection from aerosols is not guaranteed by such masks. Evaluation of the protection efficiency of non-certified mask against microbiological infection is needed for the prevention of infectious disease.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1996년도 추계학술대회 논문집 학회본부
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• pp.457-461
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• 1996

An optimum design methodology for the power MOSFET's with a predetermined mask is proposed and verified by comparing with the results of MEDICI simulation and the data of commercially available devices. Optimization is completed by determining a doping concentration and a thickness of the epitaxial layer which satisfy a specific voltage and current rating requirements as well as a minimum on-resistance for the mask set. The commercial HEX-1 mask set with a die area of $40.4{\times}10^{-3}\;cm^2$ and a T0-220 package has the on-resistance of $1.5{\Omega}$ at 200 V/2.5 A rating while the M-1 mask from this study exhibits $0.6{\Omega}$ on-resistance at 200 V/6 A. The 60 % reduction in the on-resistance and 58 % enhancement in the current rating have been obtained by the proposed method.

• 한국환경보건학회지
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• 제48권2호
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• pp.116-122
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• 2022

Background: The recent COVID-19 pandemic is one of the worst disease outbreaks of the 21th century. Due to a lack of reliable antiviral therapeutics, wearing face masks is recommended to prevent airborne infection originating from virus-contaminated bioaerosols. Objectives: The aim of this study was to evaluate the filtration efficiencies of face masks that are commercially available in South Korea for a biological aerosol of Staphylococcus aureus (S. aureus) and murine coronavirus, a well-known surrogate for human coronaviruses. Methods: We collected six different kinds of commercial masks: two Korea Filter (KF)94 (KF94-1, KF94-2) masks, one surgical (Surgical-1) mask, one anti-droplet (KF-AD-1) mask, and two dust (Dust-1, Dust-2) face masks. S. aureus (ATCC 6538), a well-performing test bacteria and murine coronavirus (ATCC VR-764) were prepared under a suitable culture condition. Then, a mask biological filtration tester was used to examine the microbial filtration efficiencies of masks. Test microorganisms were quantitatively measured via cultivation methods and microbial filtration efficiencies were calculated appropriately. Results: All face masks showed over 99.6% filtration efficiency for S. aureus or murine coronavirus. There were no significant differences among the bacterial filtration efficiencies of the face masks. KF94-1 (99.97±0.08%) and Dust-1 mask (99.97±0.07%) showed the highest (over 99.9%) filtration efficiency for murine coronavirus. KF94-1 or Dust-1 masks showed a significant virus filtration efficiency compared to Surgical-1 mask (p<0.05; Mann-Whitney U test). Conclusions: All the commercially available face masks used in this study can filter S. aureus or murine coronavirus in bioaerosols efficiently, regardless of the mask type. Therefore, our results suggest that wearing a certified face mask is a reliable means to prevent the transmission of infectious airborne diseases via biological aerosols.

• Journal of Applied Biological Chemistry
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• 제64권1호
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• pp.1-4
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• 2021

Ambient air pollution, in particular, particulate matter (PM) pollution imposes serious health concerns such as hospitalization and premature deaths, worldwide. While commercial breathing masks are in use for protection against this hazardous issue, yet their efficiency in filtering PM was not up to the par, besides several other discomforts such as poor breathability due to reduced air flow, sweat production etc. In this study, commercial face mask coated with β-glucan, a high molecular weight polymer is tested for its efficacy in filtering PM. Quantification of PM before and after filtration and microscopic observation (using scanning electron microscopy (SEM)) of the fabric used in filtering the dust pollutants (generated from wood chips and cigarette) showed that β-glucan coated fabric were significantly efficient in capturing PM (size of 10 and 2.5 ㎛ in diameter) than that of the untreated control fabric, wherein the former had filtration efficacy with fold increase of 11.6 and 2.6 towards capturing PM2.5 and PM10 respectively than the latter. Thus, β-glucan coated fabric was found to be effective in filtering PM.

• International Journal of Precision Engineering and Manufacturing
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• 제4권1호
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• pp.23-29
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• 2003

Stencil is used normally as a mask for solder pasting on pad of a printed circuit board (PCB). The objective of this study is to develop a stencil cutting system and determine the optimal conditions to make good-quality stencil by using a Nd:YAG laser. The effects of process parameters such as laser power, type of mask, gas pressure, cutting speed and pulse duration on the cut edge quality were investigated. In order to analyze the cut surface characteristics (roughness, kerfwidth, dross) optical microscopy, SEM microscopy and roughness measurements were used. As a result, the optimal conditions of cutting process parameters were determined, and the practical feasibility of the proposed system was also examined by using a commercial Gerber file for PCB stencil manufacturing.