• 한국재료학회지
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• 제27권11호
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• pp.577-582
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• 2017

Self-cleaning and photocatalytic $TiO_2$ thin films were prepared by a facile sol-gel method followed by spin coating using peroxo titanic acid as a precursor. The as-prepared thin films were heated at low temperature($110^{\circ}C$) and high temperature ($400^{\circ}C$). Thin films were characterized by X-ray diffraction(XRD), Field-emission scanning electron microscopy(FESEM), UV-Visible spectroscopy and water contact angle measurement. XRD analysis confirms the low crystallinity of thin films prepared at low temperature, while crystalline anatase phase was found the for high temperature thin film. The photocatalytic activity of thin films was studied by the photocatalytic degradation of methylene blue dye solution. Self-cleaning and photocatalytic performance of both low and high temperature thin films were compared.

• 한국건설순환자원학회논문집
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• 제10권1호
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• pp.56-65
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• 2022

본 연구에서는 시설물의 자기정화성능을 확보하기 위하여 이산화티탄 광촉매 용액을 코팅한 모르타르의 자기정화성능을 분석하였다. 광촉매 코팅 용액의 농도(1.5 %와 3.0 %), 초친수강화 용액 적용 유무 및 프라이머 용액의 사용 유무를 실험변수로 고려하였다. 광촉매 농도가 증가할수록 메틸렌블루 수용액의 색상 변화율이 증가하였으며, 이는 광촉매 농도가 증가할수록 자기정화성능이 증가하는 것을 나타낸다. 초친수성 광촉매 용액의 적용은 일반 광촉매 용액에 비해 자기정화성능을 다소 감소시킬 가능성이 있음을 나타낸다. 또한, 프라이머를 사용한 모르타르의 자기정화성능은 프라이머를 사용하지 않은 모르타르의 자기정화성능과 뚜렷한 차이를 나타내지 않는다. 한편, 낮은 농도(1.5 %)로 코팅된 모르타르에 비해 높은 농도(3.0 %)로 코팅된 모르타르 시편 표면의 코팅 균열이 미세하여 상대적으로 큰 광촉매 반응면적을 확보하고 자기정화성능 증가에 유리한 영향을 미친 것으로 판단된다.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2017년도 추계 학술논문 발표대회
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• pp.203-204
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• 2017

In case of developing a guide-rail type window cleaning robot, only the first prototype has been developed. In this study, it was considered that the size and the load of the window cleaning robot was not optimized, and through the structural analysis of the self-weight of the window cleaning robot, the stress concentration area was derived and the concentrated stress was quantified. Analysis showed that the upper rail shaft had a bending stress of 9.964Mpa and the bolt had a shear stress of 19.544Mpa. The results of this study will be used as basic data for designing future prototypes.

• International Journal of Advanced Culture Technology
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• 제3권1호
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• pp.13-20
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• 2015

The self-cleaning properties of nano-zinc oxide on cotton fabrics have been investigated. The cotton fabric has been prepared by pad-dry method. The nano-zinc oxide was encapsulated in the polystyrene particle by mini-emulsion process prior used. The loading amount of zinc oxide particles into the mini-emulsion were various from 1% wt to 40%wt. The particles sizes of ZnO-encapsulated polystyrene mini-emulsion were determined using dynamic light scattering. It was showed that the particle size of the mini-emulsion was in the range of 124-205 nm. The topography and morphology of ZnO-encapsulated polystyrene which coated on cotton fabrics was observed using scanning electron microscopy. The crystal structure of ZnO-coated on cotton fabrics was explored by X-ray diffraction spectroscopy. The photocatalytic activities of zinc oxide were present through the self-cleaning properties. The presents of the zinc oxide on cotton fabrics significantly showed the improving of the self-cleaning properties under UV radiation.

• 한국재료학회지
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• 제28권11호
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• pp.620-626
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• 2018

Highly self-cleaning thin films of $TiO_2-SiO_2$ co-doped with Ag and F are prepared by the sol-gel method. The asprepared thin films consist of bottom $SiO_2$ and top $TiO_2$ layers which are modified by doping with F, Ag and F-Ag elements. XRD analysis confirms that the prepared thin film is a crystalline anatase phase. UV-vis spectra show that the light absorption of $Ag-F-TiO_2/SiO_2$ thin films is tuned in the visible region. The self-cleaning properties of the prepared films are evaluated by a water contact angle measurement under UV light irradiation. The photocatalytic performances of the thin films are studied using methylene blue dye under both UV and visible light irradiation. The $Ag-F-TiO_2/SiO_2$ thin films exhibit higher photocatalytic activity under both UV and visible light compared with other samples of pure $TiO_2$, Ag-doped $TiO_2$, and F-doped $TiO_2$ films.

• 한국가시화정보학회지
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• 제19권3호
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• pp.123-129
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• 2021

Many plants and animals in nature have superhydrophobic surfaces. This superhydrophobic surface has various properties such as self-cleaning, moisture collection, and anti-icing. In this study, the superhydrophobic properties of PTFE surface were treated by plasma etching. There were four important factors that changed the surface properties. Micro-sized protrusions were formed by plasma etching. The most influential parameter was RF Power. The contact angle of the pristine PTFE surface was about 113.8°. The maximum contact angle of the surface after plasma treatment with optimized parameters was about 168.1°. In this case, the sliding angle was quite small about 1°. These properties made it possible to remove droplets easily from the surface. To verify the self-cleaning effect of the surface, graphite was used to contaminate the surface and remove it with water droplets. Graphite particles were easily removed from the optimized surface compared to the pristine surface. As a result, a surface having water repellency and self-cleaning effects could be produced with optimized plasma etching parameters.

• 대한전기학회논문지
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• 제40권6호
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• pp.626-629
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• 1991

The negative wire of an electrolytic ozone generator, proposed by authors, has been contaminated by attaching the impurity particulate in tap water, which is called BUILD-UP phenomenon. The higher applied voltage and the larger wire diameter have shown the higher build-up rate, which makes the current reducing largely and concurrently the ozone production smaller. It is found that the positive electrode of the ozone generator has a strong SELF-CLEANING effect by detaching the impurity particulate from its surface, which, however, is used us a novel means of solving the build-up problem. As a result, the build-up problem can be solved effectively by applying an alternate square wave pulse voltage to the electrodes so as to get the self-cleaning ability on the both electrodes during each of the half pulse duration time.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2003년도 춘계학술대회논문집
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• pp.229-233
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• 2003

The soundproof barrier used to reduce the traffic and rail noise is usually designed to the point of view of the acoustic performance such as absorption ratio and transmission loss. But, because the surface of soundproof barrier is polluted by the air pollutant or discharge gas of automobiles, so it's surface cleary maintained by the periodic washing with detergent. But in this case the environmental pollution and the working expenses are worried. So, the objective of this study is to develope the soundproof panel with the self-cleaning properties only by raining.

• 한국표면공학회지
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• 제28권1호
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• pp.23-33
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• 1995

AISI 304 stainless steel has high resistance to corrosion due to the presence of a self-healing chromium oxide film on the surface, which also accounts for the difficulty in plating. Surface cleaning of this alloy is of fundamental importance in gold plating since its effectiveness puts an upper limit on the quality of the final coating. The cleaning of AISI 304 stainless steel was investigated with elimination of artificial passive oxide film and degreasing of remaining buffing wax as stearic acid. The familiar cleaning methods i.e. ultrasonic cleaning, electro-cleaning and activation treatment were fabricated in this study. Activation treatment showed best cleaning efficiency for elimination of passive oxide film among these methods, which was also confirmed by AES (Auger electron spectrometer) analysis. However, the best condition of cleaning was obtained by combining these methods. Electrocleaning time, for degreasing the stearic acid layer, was decreased with increasing amount of added KCN.

• Journal of Oral Medicine and Pain
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• 제40권2호
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• pp.41-46
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• 2015

Purpose: This study was performed to investigate a correlation among oral hygiene habits, dryness of mouth, and self-perceived oral malodor and therefore to find out self-care methods which could be a help to reduce oral malodor. Methods: A survey of 296 dental undergraduate students of School of Dentistry, Pusan National University, who wrote consents voluntarily and participated in this study, was conducted using a questionnaire consisting of 17 questions and analyzed to investigate a correlation among oral hygiene habits (frequency of tooth brushing, water gargling, and drinking water, etc.), dryness of mouth indicating the amount of salivary secretion, and self-perceived oral malodor. Results: There was no significant correlation between mechanical cleaning factors and self-perceived oral malodor. The factor showing a strong correlation with severe self-perceived oral malodor was dryness of mouth (p=0.000). Conclusions: There was no correlation between mechanical cleaning habits and self-perceived oral malodor. Participants who felt self-perceived oral malodor more tended to have rather good mechanical cleaning habits. The factor showing a strong correlation with severe self-perceived oral malodor was dryness of mouth. Therefore trying to increase salivary secretion is considered to be a help to reduce self-perceived halitosis.