• 한국재료학회지
• /
• 제12권5호
• /
• pp.334-340
• /
• 2002

$TiO_2$-coated fly ash was synthesized by dropping method of coating agent in order to get $TiO_2$ coating layer with high photocatalytic activity on the surface of coal fly ash. The properties of the $TiO_2$ coating layer such as morphology, crystal structure, crystal size and photocatalytic activity were compared with those of the $TiO_2$-coated fly ash prepared by the traditional method of precipitation. $TiCl_4$ aqueous solution was used as a titanium stock solution and $NH_4HCO_3$ was used as a precipitant. The $TiO_2$ coating layer obtained by dropping method of coating agent was more uniform than that coated by precipitation. However, the crystal of $TiO_2$ coated by dropping method of coating agent was easy to grow by heat treatment because of the small primary particle size and bulky morphology, and its photocatalytic activity was consequently lower than that of the $TiO_2$ coated by precipitation. The $TiO_2$ coating layer obtained by both methods had a crystal structure of anatase, and the temperature of phase transformation into rutile was 90$0^{\circ}C$. The minimum crystal size of $TiO_2$ for the highest photocatalytic activity was found to be about 10nm.

• 생물환경조절학회지
• /
• 제30권4호
• /
• pp.304-311
• /
• 2021

고온기 시설멜론 재배 시 저비용 고효율의 개발하기 위하여 차광 자재별 이용 효과를 구명하고자 수행하였다. 차광처리에 따른평균온도는 무차광이 36.6℃, 차광도포제는 34.5℃, 백색차광망은 34℃로 조사되었다. 도포제 살포 직후에 투광률이 무차광에 비해서 차광 도포제 처리구는 69%, 백색차광망 처리구는 75% 이었으나, 40일 및 80일 후 차광 도포제 처리구의 투광률이 각각 92% 및 98%로 높아져 처리된 차광도포제가 서서히 제거되는 것을 알 수 있었으며, 백색차광망 처리구는 시간의 경과에 따른 투광률의 변화가 거의 없었다. 생육에 있어 엽수는 처리 간에 차이가 없었고, 초장은 무차광에 비해 백색차광망과 차광도포제 처리구에서 높게 나타났다. 엽중, 생체중, 건물중의 경우 차광 처리구에 비해서 무차광에서 정식 42일 후에는 더 무거운 것으로 나타났다. 총 상품수량은 무차광에 비해서 백색차광망과 차광도포제가 각각 6% 및 5% 증수되었다. 따라서 고온기 간편하게 온도를 낮출수 있는 방법으로 차광도포제는 효과적이나 서서히 제거되기 때문에 재배 시기를 고려해서 사용하는 것이 바람직하다고 생각되었다.

• 대한소아치과학회지
• /
• 제23권4호
• /
• pp.915-924
• /
• 1996

The purpose of this paper is to investigate the surface roughness of glass ionomer cement during initial setting time followed by applying surface coating agent. No other finishing or polishing procedure is done and each surface coating agents (varnish, adhesive, gloss, sealant) are used after filling of glass ionomer cement. Surface roughness indices(Ra) are measured and surface contours are obtained electronically by Surfcorder SEF-30D(Kosaka laboratory Ltd., Japan). The results are as follows: 1. During initial setting time, surface roughness increases slightly regardless of surface coating agents. But it is statistically insignificant. (p>0.05) 2. Among surface coating agents used, Ra indices of group using varnish are high significantly compared to other groups regardless of elapsed time.(p<0.05) Among the groups which has used other surface coating agents except for the varnish group, similar Ra index all over the experiment is obtained, when compared to control group (no agent). 3. If no surface treatment is performed, tri-cure glass ionomer cement (Vitremer) has higher Ra Index than light cure glass ionomer cement (Fuji II LC) (t<0.05). But there is no difference between two groups in Ra index if any kinds of agents are applied except for sealant. (t>0.05)

• Korean Chemical Engineering Research
• /
• 제54권6호
• /
• pp.767-774
• /
• 2016

졸-겔법에 의해 출발물질로 aluminum isopropoxide를 사용하여, 메탄올용매 내에서 가수분해 시킨 후 해교제인 초산, 질산 또는 염산을 각각 첨가하여 해교 시켜 3종류의 alumina sol을 제조하였다. 또한 이 sol에 실란커플링제인(3-glycidyloxypropyl) trimethoxysilane을 첨가하여 코팅 용액을 제조한 후, 이용액을 polycarbonate 기재 위에 담금 코팅 후 열 경화시켜 코팅 도막을 형성하였다. 이 과정 중 해교제의 종류 변화가 코팅 도막의 물성에 미치는 영향을 연구하였다. 그 결과 해교제로서 강산인 염산이나 질산을 사용한 코팅 도막은 H나 2H의 연필경도와 5B의 부착력을 나타내어 우수한 물성을 나타내었다. 반면에 해교제로서 약산인 초산을 사용한 경우에는 HB의 연필경도와 3B의 부착력을 보여 좋지 못한 물성을 나타내었다.

• 한국표면공학회지
• /
• 제48권2호
• /
• pp.56-61
• /
• 2015

In this study, the wear performance of manganese phosphate coating on SM45C with addition agent of Tartaric acid and Citric acid were investigated. The Surface morphology of manganese phosphate coating was examined by Scanning Electron Microscope (SEM) and Energy Dispersive X-ray spectroscopy (EDS). It is found that Mn, P, Fe, O and C. The crystal structure and thee composition was analysis and determined by using XRD. The XRD results indicated that manganese phosphate coatings are mainly composed of $(Mn,Fe)_5H_2(PO_4)_44H_2O$ and consists of a lot of close packed lump crystalline. Based on the time dependence of morphology and the weight of manganese phosphate coating, it shows that the phosphating process mainly includes three stages: corrosion of the substrate, creation and growth of phosphate crystal nucleus and thickening of manganese phosphate coating. The wear tests were performed in a ball on disc apparatus as per ASTM G-99 Standard. It was showed that the initial wear was quite high followed by low sludge.

• 한국응용과학기술학회지
• /
• 제30권1호
• /
• pp.96-115
• /
• 2013

본 연구는 항균성 코팅제의 개념과 동향파악으로 항균성 코팅제의 연구개발의 방향을 설정하는데 도움을 주기 위한 것이다. 항균제는 미생물을 제거하거나 성장을 저지하는데 사용되는 화합물이며 항균 코팅제에 함유되는 항균제용 재료는 무기물, 금속, 저분자 유기물, 천연유기물, 고분자가 있다. 항균코팅제는 생활용품, 병원용품, 산업용품, 전자제품, 의류, 건축 내장재 등의 표면의 항균성 부여에 쓰인다. 기존 항생제는 세균의 세포벽을 손상하지 않고 미생물을 침투하나 항균성 고분자는 세포막을 파괴하므로 항생제의 내성을 방지할 수 있다. 대부분의 고분자 항균제는 양이온 고분자에 초점을 맞추고 있다. 항균제의 분자설계와 코팅제 배합의 합리화로 항균제의 선택성, 내구성, 독성 문제가 개선될 것이다.

• 한국건축시공학회지
• /
• 제14권1호
• /
• pp.21-28
• /
• 2014

경량골재의 내부공극을 통한 탄산가스 유입으로 인해 경량골재콘크리트는 보통콘크리트에 비해 탄산화가 더 빠르게 진행되는 문제점을 극복하고자, 4가지 표면코팅제로 코팅된 경량골재를 사용한 콘크리트에 대하여 탄산화 저항성을 보통 경량골재콘크리트, 보통콘크리트와 비교 분석하였다. 코팅경량골재를 사용한 콘크리트가 보통 경량골재콘크리트보다 우수한 탄산화 저항성을 보였으며, 특히 발수제보다는 고분자계 코팅제를 사용하였을 때 더 우수한 저항성을 나타내었다.

• Corrosion Science and Technology
• /
• 제7권6호
• /
• pp.344-349
• /
• 2008

Epoxy coatings were prepared to give a different corrosion protection by reacting it with two different kinds of curing agent, and then effects of the curing agents on the structure, surface hydrophobic tendency, water transport behavior and hence corrosion protection of epoxy coatings were examined using hygrothermal cyclic test, and impedance analysis. In the results of EIS, the corrosion protection of epoxy coating cured by polyamide shows better than epoxy coating cured by polyamide epoxy adduct. It was well agreed with its water transport behavior and hydrophobic tendency.

• 한국자동차공학회논문집
• /
• 제22권5호
• /
• pp.5-12
• /
• 2014

Weatherstrip coatings of urethane and silicon type which are fit to EPDM and thermoplastic materials are used in sealing systems for automotive applications for noise reduction and high slip characteristics for external applications, respectively. Polyurethane binder was successfully synthesized from poly(butyladiphate)diol (PBAD), poly(tetramethylene)glycol (PTMG) and isocyanate as starting materials. Then, polyurethane coating agents were prepared by using various additives. To investigate effects of segment types on the abrasion resistance of polyurethane coating agents, thin films based on polyurethane coating materials were fabricated. With increasing the amount of hard segment in the coating agent, abrasion resistance, modulus and tensile strength of the coating films were improved, but the elongation of the coating films was decreased.

• Smart Structures and Systems
• /
• 제4권4호
• /
• pp.439-448
• /
• 2008

Optical fiber sensors are by now broadly accepted as an innovative and reliable device for structural health monitoring, to be used either embedded into or bonded on structures. The accuracy of the strain measurement achievable by optical fiber sensors is critically dependent on the characteristics of the bonding of the various interface layers involved in the sensor bonding/embedding (structure material and gluing agent, fiber coating and gluing agent, fiber coating and fiber core). In fact, the signal of the bonded/embedded optical fiber sensor must correspond to the strain experienced by the monitored structure, but the quality of each involved interface can affect the strain transfer. This paper faces the characterization, carried on by both mechanical tests and morphological analysis, of the strain transfer function resulting with epoxidic and vinylester gluing agent on polyimide and acrylate coated optical fibers.