• 한국가구학회지
• /
• 제26권3호
• /
• pp.262-266
• /
• 2015

This study was carried out to analyze the surface color change according to the weathering time. The surface color of material was one of evaluation indexes in exposure experiment. For the purpose, accelerated weathering test was performed with wood. The weathering time level was composed with 0, 500, 1000, 1500 and 2000 hours and color difference was estimated with the color difference meter. The surface color was changed to 500 hours that lightness and redness were decreased and yellowness was increased. However it did not changed after 500 hours. It means that the surface color could be the evaluation index of deterioration of the wood but it means very little after certain time.

• 한국표면공학회지
• /
• 제55권6호
• /
• pp.383-389
• /
• 2022

Natural(outdoor) and accelerated(artificial) weathering tests were performed to investigate their influence on polycarbonate. The polycarbonate materials were prepared of various formulations divided into three batches, with existing, development materials1, development materials2, containing mixture of UV additives. Weathering tests were carried out as outdoor weathering(Seosan, South Korea) and accelerated weathering(xenon-arc), and the results analysis were evaluated based on yellow-index(YI), scanning electron microscope(SEM/EDS), energy dispersive x-ray spectroscopy(XRD), and gel permeation chromatography(GPC). Among the three materials, processing method development materials1 with UV stabilizer was excellent in weathering. This study can provide basic data for standardization of development and performance evaluation on livestock barn roof.

• 한국결정성장학회지
• /
• 제6권4호
• /
• pp.640-647
• /
• 1996

하절기에 장시간 창고에 보관된 일반 소다-라임-실리케이트 유리는 특별한 표면처리를 하지 않는 한 백색물질이 표면에 석출되는 weathering 현상이 나타날 수 있다. 본 연구는 유리병 내벽 표면에 생성된 백색물질을 습식법 및 표면분석법 등을 이용하여 분석하고 대기의 변화에 따른 weathering 정도를 연구하였다. 표면에 석출된 백색의 물질은 육각관상의 Na$_2$CO$_3$${\cdot}$H$_2$O와 CaCO$_3$로 규명되었다. 해안지방에서 제조-보관되었던 유리병 표면은 내륙지방의 유리병에 비해 weathering된 깊이가 3배 정도로 그 정도가 심하여 weathering이 대기중의 수분량에 크게 의존함을 알 수 있었다.

• Elastomers and Composites
• /
• 제51권4호
• /
• pp.350-354
• /
• 2016

The surface properties of poly(methyl methacrylate) (PMMA) were investigated after accelerated weathering. Glossinesses, contact angles, surface free energies, thermal stability, and mechanical properties were investigated. The glossiness of the weathered PMMA was decreased with increasing exposure time. Contact angles and surface free energies were not overtly changed because the amount of oxygen on the surface was remained. PMMA was compounded with anti-block and antistatic agents using a co-rotating twin screw extruder to improve the durability. The PMMA composites showed better glossinesses after accelerated weathering while maintaining the contact angles, surface energy, thermal stability, and mechanical properties without significant changes.

• 광물과 암석
• /
• 제35권3호
• /
• pp.299-311
• /
• 2022

지표에 노출된 암석은 지속적으로 풍화를 받게 되고 이러한 영향으로 암석의 공학적 안정성이 약해지게 된다. 특히 풍화가 진행되면서 암석의 표면은 풍화에 의해서 변화를 일으키고 이러한 표면 변화는 암석으로 구성된 지반의 공학적 안전성에 영향을 미치게 된다. 또한, 풍화를 받은 암석에서 생성되는 화학종은 주변환경에 직접적인 영향을 미치거나 구조물에 영향을 미치게 된다. 광산지역과 같이 암석이 노출된 지역에서는 풍화에 의해 생성된 화학종이 주변 자연환경에 심각한 영향을 미치기도 한다. 본 연구에서는 이러한 관점에서 동결/융해 실험을 활용한 풍화가속 실험을 이미 풍화를 받은 암석과 신선한 암석을 대상으로 실시하고 각 암석의 표면 변화를 다초점 레이저 현미경으로 관찰하고 IC/ICP-MS를 활용하여 화학종 생성에 대한 분석을 실시하였다. 풍화가 진행됨에 따라 표면의 거칠기는 완화되는 것을 확인하였고 주변환경에 영향을 미칠 수 있는 화학종은 풍화를 받는동안 양이 증가하는 것을 확인하였다. 본 연구 결과는 암석이 노출된 지역에서의 공학적/환경학적 안전성을 평가하는 기초 자료로 활용될 수 있을 것이다.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 2003년도 추계학술대회 논문집 Vol.16
• /
• pp.243-247
• /
• 2003

The effect of accelerated weathering(UV) on three type of ethylene propylene diene monomer(EPDM) composite used for higher voltage insulator were investigated by weather-emoter. For weatherability of EPDM composite, surface resistance, dielectric breakdown strength, change of contact angle, surface composition were measured according to UV accelerated weathering time. From the resort of the measurement of surface resistivity, contact angle of EPDM composite decreased and showed chalking and cracking phenomenon when UV weathweing time was for 1500 h and 2000 h. The analysis of surface atomic composition indicated that surface aluminiu(Al) content was detected due to chalking phenomenon after 1500 h of UV weathering, Oxygen content of all composite increased due to the oxidation.

• 한국지반공학회:학술대회논문집
• /
• 한국지반공학회 2008년도 춘계 학술발표회 초청강연 및 논문집
• /
• pp.875-883
• /
• 2008

The amount of granite distribution area occupies about 40 - 50% of Korean Peninsula. The granite irregularly Intruded through preCambrian to Tertiary times but in Jurassic time so called, Daebo granite most widely crops out in Korean Peninsula. In addition to Bulkuksa Grante which intruded at Cretaceous time crops out at the southern part of Korean Peninsula and in northern part Triassic Songrim Granite is distributed. These granites have equigranular texture and are relatively isotropic. Their uniaxial compressive strength is above $1,500kg/cm^2$ and also seismic velocity is over 2,000m/sec. When these rocks receive a weathering action, the feldspar weathers first and the quartz grains remain plentifully to make the "Masato(Korean name)". Also when the granite receives a weathering action, quite often it make sheeting joint which is topographically parallel to the earth surface and also make a (so called, onion structure. These weathering phenomena easily make a land sliding when it is heavy rain and weathering surface is irregular.

• 보존과학연구
• /
• 통권28호
• /
• pp.39-58
• /
• 2007

The Seated Buddha image carved on rock surface of Yuneulgok in Bae-ri, Gyeongju constituted of alkali feldspar granite. There is surface weathering by abrasion, exfoliation and break out. As a result various experiment was carried out testing rock material property to quantitatively grade weathering. Besides, this study is focused on properties of rock and correlation between things. Additionally, comparison of chemical properties to nondestructive weathering grade in the buddha image carved on rock. This result utilized on important resource for scientific conservation system compared with weathering appearance.

• 한국지형학회지
• /
• 제25권1호
• /
• pp.47-65
• /
• 2018

Frost shattering has traditionally been considered as one of the most effective process in rock weathering. Each slab specimens of five or six rhyolite, basalt and tuff was prepared and put in freeze-thaw cycles and repeated 300 times in the temperature of $-25^{\circ}C$ to $+30^{\circ}C$ and their weathering patterns and products were analyzed by surface observation, particle size, XRD and thin section. As the result, some changes were observed in weathering patterns and weathering products. Rock shattering was more active in waterlogging rather than atmospheric conditions, but there are many differences depending on the type of rock. Rhyolite is hardly weathered by 300 times freeze-thaw cycles and generates the least amount of weathering products. Weathering of Basalt is limited to the surface layer where water can be absorbed, and produces a few amount of platy-shape debris. Tuff are separated by blocky structure which the particles are aggregated along their edges rather than enlarged existing cracks/joins or generated new joints.

• 한국철도학회:학술대회논문집
• /
• 한국철도학회 2004년도 추계학술대회 논문집
• /
• pp.988-993
• /
• 2004

This paper considers corrosion problems in the bolt connection of weathering steel box girder bridge using the external electric type corrosion resistance method which resisted to local corrosion in coated steel surface with contacted air. The weathering steel was created a rust itself in the passive state. but a coated box girder type was easily dew form could be made galvanic cell that accelerated corrosion. so that it was ruled by protection coat with some paint. Therefore, it needed that can be applied the external electric type corrosion resistance method in coated surface. As a result of the test of polarization amount had measured that the weathering steel was higher currents than the general steel by about $5\~10\%$. Therefore. an external electric type corrosion resistance method can be used to protect local corrosion in the coated bolt connection of weathering steel box girders effectively.