• Proceedings of the Optical Society of Korea Conference
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• 2003.07a
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• pp.256-257
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• 2003

Composite materials are widely used in industry because of its high ration of strength vs. weight, and consequently many nondestructive methods have been developing to find stress or subsurface defects like crack, and delamination inside composite material. Among them, optical inspection methods have been widely neglected because of translucent or opaque nature of composite. (omitted)

• 한국초전도학회:학술대회논문집
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• 2007.07a
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• pp.82-82
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• 2007

• Transactions of Materials Processing
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• v.18 no.6
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• pp.444-447
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• 2009

Piston crown to the hot forge a unified nature of the product has a shape with multi-level step forging process, so if you are not a mechanical professional, this process could lead to a significant loss to the material. Therefore, material technology in minor terms; continue to improve the collection rate that undamaged the product material. The piston crown and the manufacturing products such as marine diesel engines are being forged to reduce costs and to improve mechanical properties. Piston crown molding is a hot forging process that works in large volume forging products. Because of the size of the hard plastic material flow process for improving the design and actual field experience through advanced plastic technology, it is important to interpret the results. Also for many experimental plastic procedures, the accumulation of results is very important.

• The Research Journal of the Costume Culture
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• v.7 no.1
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• pp.13-26
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• 1999

The purpose of this study was to identify the origin of diversity of costume material caused by environmental difference. For this purpose, this research involved theoretical studies and studies based on historical data obtained from previous related studies. The common truth was proved that environmental including the geographical distribution of plants and animals determines costume material. Also, It was found that the unique traditional costume styles were developed through unique combination of costume material and their culture. The major results of this study are as follow : 1. The traditional costume of North American Indian was well-developed and closely related to geographical distribution of plants and animals. Also, their costume was so diverse that it could not be categorized. 2. The traditional costume of North American Indian showed ideal har mony between nature and human being surrounding environment into their costume. 3. The application of plants and animal materials into their costume was one of the environment-friendly human activity and it seems to give us an important message.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2003.11a
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• pp.133-137
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• 2003

When a light is projected upon a material, part of its radiation energy is absorbed and the rest is reflected or transmitted according to the nature of the material. The molecules of the substance absorbing a light obtains the radiation energy to the wavelength of the light to make photochemical degradation by ultraviolet ray or thermal reactions like physical damage by infrared ray. The degree of damage by radiation energy varies to the substances of materials, the spectral power distribution of the light source and the duration of irradiation. Because the damage brings about a devaluation of material and once damaged, it is irretrievable, it is necessary to minimize the damage and conserve the native quality of a material by a protective lighting system. A measuring system was set up to measure the temperature rise of each sample by infrared radiation from light sources. And the temperature rise and temperature distribution by various infrared lamps were measured with varying time.

• Journal of the Korean Ceramic Society
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• v.51 no.2
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• pp.103-106
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• 2014

Nacre is an organic-inorganic composite material; it is composed of $CaCO_3$ platelet and protein. The microstructure of nacre is a matrix that is similar to bricks and mortar. Technology inspired by nature is called biomimetic technology. In this study, to make high thermal conducting ceramic composite materials using biomimetic technology, a porous green body was prepared with BN platelets. PMMA was infiltrated into the porous green body to make a composite. The microstructure of the composite was observed with FESEM, and the thermal properties were measured. The thermal conductivity of the prepared organic-inorganic composite was 4.19 $W/m{\cdot}K$.

• Transactions on Electrical and Electronic Materials
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• v.15 no.6
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• pp.291-296
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• 2014

In recent years, researchers have extensively investigated polymers filled with inorganic nanoparticles because these materials present improved physical properties relative to those of conventional unfilled polymers. Oxides, silica in particular, are the most commonly used inorganic particles because they possess good properties and can be fabricated at a low cost. However, oxides are hydrophilic in nature, and this leads to the presence of water at the interface between the nanoparticles and the polymer matrix. Due to the predominance of particle-matrix interfaces in nanocomposites, the presence of water at the interlayer region can be problematic. Moreover, the hydrophobic nature of most polymers, particularly for polyolefins such as polyethylene, may make it difficult to remove this interfacial water. In this paper, as-received and moistened samples of agglomerated nanosilica/polyethylene were dried using an isothermal treatment at $60^{\circ}C$, and the efficacy of this treatment was studied using dielectric spectroscopy. The Maxwell-Wagner-Sillars relaxation peaks were observed to shift to lower frequencies by three decades, and this was linked to a modification of the water content, due to drying, at the interfaces between silica and polyethylene and at the interfaces within the nanosilica agglomerates. The evolution of the extracted retardation time is explained by the nanosilica hydrophily and the free volume introduced by the nanoparticles.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.27 no.10
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• pp.1754-1761
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• 2003

The atomic force microscopy (AFM) based lithographic technique has been used directly to machine material surface and fabricate nano components in MEMS (micro electro mechanical system). In this paper, three-dimensional molecular dynamics (MD) simulations have been conducted to evaluate the characteristic of deformation process at atomistic scale for nano-lithography process. Effects of specific combinations of crystal orientations and cutting directions on the nature of atomistic deformation were investigated. The interatomic force between diamond tool and workpiece of copper material was assumed to be derived from the Morse potential function. The variation of tool geometry and cutting depth was also evaluated and the effect on machinability was investigated. The result of the simulation shows that crystal plane and cutting direction significantly influenced the variation of the cutting forces and the nature of deformation ahead of the tool as well as the surface deformation of the machined surface.

• Journal of Haehwa Medicine
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• v.22 no.2
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• pp.23-35
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• 2014

Gu-Hwang Plants(plants collected from mountains and fields and eaten when no food was available) is healthy, life saving food material, being Mi(taste) and Ki(energy) of nature, for modern people who lose their health by oversupplying energy and unbalanced diet. Also, Gu-Hwang Plants is material for new medicine and functional foods. However, there is a lack of document research about Gu-Hwang plants in Korea. "Gu-Hwang-Bon-Cho" is a book about plants written as a guide for collecting food from nature and maintaining life at times when no food is available due to natural disaster. The book describes in which soils the plants are produced and the names for the plants, and classifies them according to hot and cold characters and sweet and bitter tastes of the plants. In addition, the book distinguished plants' edible parts, such as flower, fruit, root, stem, peel, and leaf, with how to collect and cook them. The book is of great value that it is reprinted over generations and now there are 30 kinds of existing books. This study conducted research based on books published throughout history which are the first book of this kind by Ju-wang-ju, a book published in 1525 by I-Ryeom, a book published in 1555 by Youk-gan, a book published by Ho-seung of Sa-cheon, and a book published in 1566 by Ju-gon.

• Journal of the Korean Society of Earth Science Education
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• v.5 no.2
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• pp.158-165
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• 2012

With five gifted and nine average elementary school students, this study attempted to make a comparative analysis on the characteristics of their scientific writings for earth science-related topics. The analysis found that all of the gifted students showed higher scores than the average in the writing sections of scientific nature, logical nature and creativity. Compared to the average scores, their creativity scores were far higher. By comparing and analyzing the predicates in the writings two groups wrote, I found that the gifted students used more sentences per topic than the average students. Both groups wrote the most numbers of sentences for Volcano-related topics. In the meantime, the gifted children used the least numbers of sentences for the related topics to atmospheric pollution and the average students did so for the related topics to fossils. By the analysis on the patterns of predicate, it was observed that both groups used material predicates most and verbal predicates least. As far as the second most used predicates are concerned, the gifted children used relational predicates and the average students used mental predicates.