• Composites Research
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• v.13 no.3
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• pp.21-29
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• 2000

The optimum design of hybrid laminated composites for iso-strain structure has been studied by controling fiber orientations and thicknesses of each layer. Fiber orientations and thicknesses of each layer for iso-strain structure were designed. Combining the laminates of each layer of different reinforcing material, the constitutions of hybrid laminated composite for iso-strain structure were obtained. All these calculations were formed on computer systems, automatically for the hybridization. Using the data of some specific laminated composite such as glass and aramid reinforced composites, the constitutions of hybrid laminated composites for iso-strains structure were designed and verified by lamination theory. The strains of each layer of hybrid laminated composites are calculated and they turned out to be good agreements with the results obtained lamination theory.

• Journal of Pharmacopuncture
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• v.11 no.3
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• pp.79-91
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• 2008

Objective: The purpose of this study was to investigate the composition for pharmacopunctures of eight principles hydrodistillation layer. Methods: The study was determined the hydrodistillation layer for pharmacopunctures of eight principles by hydrodistillation method. The effective components in hydrodistillation layer for pharmacopunctures of eight principles were extracted with ethyl ether or dichloromethane, and then analyzed by Gas Chromatography/Mass Spectrometry(GC/MS). Results: 1. Analyzed pharmacopunctures of eight principles by GC/MS, a lot of differences according to extraction solvent by each pharmacopunctures of eight principles and specific peak patterns were seen. 2. The main compound in pharmacopunctures of eight principles was a kind of hexaoxacyclohydrocarbon that has long hydrocarbon chain.

• Proceedings of the Materials Research Society of Korea Conference
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• 2011.05a
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• pp.9.2-9.2
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• 2011

Ultrathin polyelectrolyte (PE) multilayer films prepared by the versatile layer-by layer (LbL) assembly method have been utilized for the preparation of light-emitting diodes, electrochromic, membrane, and drug delivery system, as well as for selective area patterning and particle surface modification because the various materials with specific properties can be inserted into the film with nano-level thickness irrespective of the size or the shape of substrate. Since the introduction of the LbL technique in 1991 by Decher and Hong, various hydrophilic materials can be inserted within LbL films through complementary interactions (i.e., electrostatic, hydrogen-bonding or covalent interaction). In this study, it is demonstrated that LbL SA multilayer films based on nucleophilic substitution reaction can allow the preparation of the highly efficient magnetic and/or optical films and nonvolatile memory devices.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.17 no.7
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• pp.764-769
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• 2004

In order to reduce operating voltage of the GaN based blue-violet laser diodes, the effect of highly Mg doped GaN layer, which was grown below ohmic contact metals, on contact resistivity as well as operating voltage has been investigated. The addition of the highly Mg doped GaN layer greatly reduced contact resistivity of Pd/Pt/Au ohmic contacts from $5.2 \times {10}^-2 \Omegaㆍ$\textrm{cm}^2$ to 7.5 \times {10}^-4 \Omegaㆍ$\textrm{cm}^2$$. In addition, it also decreased device voltage at 20 mA by more than 3 V. Temperature- dependent sheet resistivity of the highly Mg doped GaN layer suggested that the reduction of the contact resistivity could be attributed to predominant current flow at the interface between the Pd/Pt/Au contacts and p-GaN through a deep level defect band, rather than the valence band.

• Applied Chemistry for Engineering
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• v.24 no.2
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• pp.201-207
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• 2013

In this study, the surface of a phenol based activated carbon (AC) used as an electrode in an electric double layer capacitor was modified via boric acid treatment for the capacitance investigation. The effect of boric acid treatment on electrochemical performance was also investigated. The AC surface functional groups ratio of quinone-like (O=C) which is electrochemical active functional groups was increased after the boric acid treatment. And, boric acid treated AC showed an increase in the specific surface area, total pore volume, and micropore volume. In case of optimum boric acid treated AC, its specific capacitance increased by 20% in comparison to that of untreated AC. These results demonstrate that a boric acid treated carbon surface-based electric double layer capacitor electrode effectively enhances specific capacitance.

• Journal of the Korean institute of surface engineering
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• v.46 no.5
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• pp.216-222
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• 2013

In order to improve the performance of electrodeposited diamond-nickel composite, surface modification of diamond particles was carried out using powder immersion reaction assisted coating (PIRAC). Titanium and chromium were selected as coating elements, which are known as carbide former. With respect to the powder elements, various phases were formed on diamond; metallic Ti and TiC for Ti powder, $Cr_3C_2$ for Cr powder, and TiC and $Cr_3C_2$ for Ti-Cr mixed powder. Surface modified diamond particle showed higher specific surface area, especially Ti coating induced considerable increase of specific surface area. The increase of specific surface area suggests increase of surface roughness, and that was confirmed by surface observation using FE-SEM. In addition, wear properties of diamond-nickel composite including surface modified diamonds were improved, and Ti coated diamond showed the highest performance. The wear property of diamond-nickel composite is dependent on adhesion strength between diamond particle and nickel layer. Therefore, surface modification of diamond particle by PIRAC increasing surface roughness is effective to improve the properties of diamond-nickel composite.

• Journal of the Korean Society for Precision Engineering
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• v.14 no.9
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• pp.146-154
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• 1997

Ion implantation has been used successfully as a surface treatment technology to improve the wear. fatigue and corrosion resistances of materials. A modified surface layer by ion implantation is very thin(under 1 m), but it has different mechanical properties from the substrate. It has also different wear characteristics. Since wear is a dynamic phenomenon on interacting surfaces with relative motion, an effective method for investigtating the wear of a thin layer is the observation of wear process in microscopic detail using in-situ system. The change of wear properties produces the transition of wear mode. To know the microscopic wear mechanism of this thin layer, it is very important to clarify its microscopic wear mode. In this paper, using the SEM and AFM Rribosystems as in-situ system, the microscopic wear of Ti ion-implanted 1C-3Cr steel, a material for roller in the cold working process, was investigated in repeated sliding. The depth of wear groove and the speciffc wear amount were changed with transition of microscopic wear mode. The depth of wear groove with friction cycles in AFM tribosystem and specific wear amount of Ti ion-implanted 1C-3Cr steel were less about 2-3 times than those of non-implanted 1C-3Cr steel. The microscopic wear mechansim of Ti ion-implanted 1C-3Cr steel was also clarified. The microscopic wear property was quantitatively evaluated in terms of microscopic wear mode and specific wear amount.

• Journal of Applied Biological Chemistry
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• v.58 no.1
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• pp.9-11
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• 2015

Tissue extracts were prepared from liquid-cultured Arabidopsis and reacted with UDP-[$^3H$]-GlcNAc. Phospholipid fractions were then extracted by butanol partitioning. Consecutive thin-layer chromatography identified two glycolipids sensitive to PI-specific phospholipase C, known as early intermediates in glycosylphosphatidylinositol anchor biosynthesis; phosphatidylinositol N-acetylglucosamine and phosphatidylinositol glucosamine.

• Tribology and Lubricants
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• v.5 no.2
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• pp.42-47
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• 1989

The thermal behaviour of layerd solids, typified in practice by surface coated materials, is evaluated for the specific case of a fast moving heat source. This is intended to represent the particular instance of solids in sliding contact and the consequences of friction. The finite difference method has been utilised to establish the temperature distributions at the surface and also the sub-surface region for coating materials which are either less conductive or more conductive than the substrate to which they are attached. The effects of variation in layer thickness, and also the load, speed and friction coefficient, are evaluated.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.17 no.1
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• pp.107-111
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• 2004

This work describes the effect of composite conductor on the characteristics of electric double layer capacitor. Test cell, which was fabricated with conducting composite consisted of 80％ of SPB and 20％ of VGCF, exhibits the better tate capability and the lower resistance than those of the cells fabricated with single electronic conductor. These enhanced properties could be related with the decrease of contact resistance between the activated carbon powders.