• 한국세라믹학회지
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• 제47권1호
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• pp.66-70
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• 2010

This article presents a brief review of our recent studies on flowerlike nanostructured $CeO_2$ materials. These materials are monodispersed microspheres with peony appearance, open mesoporous structure, large specific surface area and nano-crystalline feature. The applications of this type of novel material to SOFC, ethanol steam reforming and CO oxidation are introduced.

• 공업화학
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• 제21권5호
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• pp.564-569
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• 2010

박막 및 디스플레이 분야에서는 광학 부품소재의 우수한 광 투과성과 투명성을 요구하는 수요가 증가함에 따라 우수한 반사방지 특성의 부여에 대하여 관심이 집중되고 있는 실정이다. 본 연구에서는 반사방지 기능을 부여하기 위하여 졸-겔법에 의한 수열합성법을 통하여 기저 물질 표면에 산화알루미늄을 나노 크기 꽃 형태의 프레임 구조를 가진 단일 산화물층을 형성시키고자 하였다. 코팅 층 시편의 특성은 UV-Vis 분광기, FT-IR 분광기, XRD 및 FE-SEM을 이용하여 분석하였다. 알루미나 졸이 코팅된 시편들의 모폴로지는 수열합성의 온도와 시간 및 초음파 제공에 의해 조절되도록 하였다. 꽃 형태의 나노 프레임 구조 형태로 구성된 코팅 층에서 높은 광투과율과 반사방지특성이 발현되었다.

• Korea-Australia Rheology Journal
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• 제15권1호
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• pp.27-33
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• 2003

Associating polymers are hydrophilic long-chain molecules to which a small amount of hydrophobic groups (hydrophobes) is incorporated. In aqueous solution, the association interactions result in the formation of three-dimensional network through flowerlike micelles at high concentrations. In colloidal suspensions, the associating polymers act as flocculated by bridging mechanism. The rheological properties of suspensions flocculated by associating polymers end-capped with hydrophobes are studied in relation to the bridging conformation. At low polymer concentrations, the polymer chains effectively form bridges between particles by multichain association. The suspensions are highly flocculated and show typical viscoelastic responses. When the polymer concentration is increased above the absorbance at saturation, the excess polymer chains remaining in the solution phase build up three-dimensional network by associating interactions. Since the presence of particles does not significantly influence the network structures in the medium, the relative viscosity, which gives a measure of the degree of flocculation is decreased with increasing polymer concentration. The bridging conformation and flocculation level vary strongly depending on the polymer concentrations.

• 건축역사연구
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• 제18권6호
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• pp.103-126
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• 2009

This study aims to discover historical trends and change of form of all stupas in India with observation of field study that is as direct as possible, by classifying, analyzing, and synthesizing the stupas. Study of Indian stupa in Korea has a number of shortcomings since only introductory partial approach has been made in order to seek the origin of Korean pagoda. This study also aims to correct errors of stupa terminology in Chinese character committed by misinterpretation of Hindi language which was established by precedent Japanese scholars several decades ago. Piled-up stupas were totally destroyed by pagans, therefore their remains tell us only of structure, material, sizeand disposition. However remains of carved stone at torana and drum give us clues as to the original form of stupa and worshipping activity, as well as change to a more luxurious form. Many rock cave stupas of India show us both simple forms matching the ascetic age of early Buddhism and luxurious changes in Mahayanan era introducing us to statues of Buddha. Indians recovered the spheric form of 'anda,' a Hindi term meaning cosmic egg, from the hemispheric form of the piled-up stupa. Therefore we might discard the erratic term of 'bokbal', which means an upset vessel. Railings and parasols became main factors of stupa design. Carved railings around stupa became a sign of divinity. Serious worshipping activity made drums long or high and created multi-embossed stripes. Bases of circular drums of some cave stupas changed their shapes to rectangular or octagonal. Single parasols became multiparasols of affluent flowerlike curved stems on carved stupa. Multistoried, elongated and high parasols of Gandhara stupas are closely related to such factors as diverse changes of form in Indian subcontinent. Four-sided torana gate and ayaka column of the circular form of original stupas suggest the rectangular form of subsequent East Asian pagoda, and higher and wider base of Indian stupas became the origin of East Asian rectangular pagoda.