• The Journal of the Petrological Society of Korea
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• v.26 no.4
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• pp.311-325
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• 2017

Peridotite xenoliths in middle Miocene alkaline basalt from the Mt. Baekdu area are mainly anhydrous spinel lherzolites, displaying coarse-grained protogranular texture. These xenoliths have late-stage secondary orthopyroxene replacing olivine as the metasomatic mineral and glass formed along the grain boundaries. The studied xenoliths are characterized by the high $Mg{\sharp}[=100{\times}Mg/(Mg+Fe_{total})$ atomic ratio] of olivine, orthopyroxene and clinopyroxene (89~92) and the $Cr{\sharp}[=100{\times}Cr/(Cr+Al)$ atomic ratio] of spinel (10~29). Based on major-element data, the studied xenoliths are similar to those from the abyssal peridotites. Clinopyroxenes of the xenoliths are mostly enriched in incompatible trace elements, exhibiting two types of REE patterns: (1) LREE-depleted with $(La/Yb)_N$ of 0.1~0.2 and $(La/Ce)_N$ of 0.4~0.8. (2) LREE enriched with $(La/Yb)_N$ of 2.2~3.8 and $(La/Ce)_N$ of 1.2~1.6. The calculated equilibrium temperatures and oxygen fugacities resulted in $920{\sim}1050^{\circ}C$ and ${\Delta}fO_2(QFM)=-0.8{\sim}0.2$, respectively. It is suggested that the Mt. Baekdu peridotite xenoliths represent residues left after variable degrees of melt extraction(less than 15 vol%), which was subsequently subjected to different degrees of modal/cryptic metasomatism by silica- and LREE-enriched fluids (or melts).

• Polymer(Korea)
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• v.36 no.5
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• pp.668-676
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• 2012

In this study, we modified silica nanoparticles with bis[3-(trimethoxysilyl)propyl]amine (BTMA) silane coupling agent to introduce secondary amino groups on the silica surface. After modification of silica, we investigated effects of different types of (meth)acrylate group containing monomers on the Michael addition reaction to introduce reactive (meth)acrylate groups on the BTMA modified silica surface. We used two kinds of (meth)acrylate monomers, trimethylolpropane ethoxylate triacrylate (TMPET) which has three identical acrylate groups, and 3-(acryloyloxy)-2-hydroxypropyl methacrylate (AHM) which has one acrylate and one methacrylate group. We used fourier transform infrared spectroscopy (FTIR), elemental analysis (EA) and solid state cross-polarization magic angle spinning (CP/MAS) nuclear magnetic resonance spectroscopy (NMR) to understand reactions between NH groups on the silica surface with (meth)acrylate groups of TMPET and AHM monomers. We found almost complete Michael addition reaction between all three acrylate groups of TMPET with NH groups on the BTMA modified silica. But, for the AHM treatment of BTMA modified silica, we found Michael addition reaction occurred only between acrylate groups of AHM and NH groups of silica surface, not between methacrylate groups of AHM and NH groups of BTMA modified silica surface.

• Transactions of the Korean Society of Mechanical Engineers
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• v.8 no.3
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• pp.283-287
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• 1984

본 연구에서는 가공 원공의 위치 및 내경을 인식할 수 있는 간단한 컴퓨터 시 각 시스템을 개발하였다. 아날로그 영상 자료로 부터 디지탈 자료를 얻기 위한 시스 템은 폐쇄회로 TV 카메로와 제어 회로 및 A/D변환기와 schmitt trigger를 부대한 마이 크로 컴퓨터로 이루어 졌으며 원공을 인식하는 알고리듬은 기울기(gradient) 기법을 이용한 경계법(thresholding)과 최소자승법에 의한 curve fitting으로 구성되어 있다. 개발된 시스템은 real time 방식이 아님에도 불구하고 검사 원공의 위치 및 내경을 영 상해상도의 오차 범위 내에서 실험을 통하여 보였다.

• Proceedings of the Korea Water Resources Association Conference
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• 2020.06a
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• pp.87-87
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• 2020

최근 기후변화에 의한 이상기후에 따라 집중호우가 빈번히 발생하고 있으며, 집중호우로 인해 내수, 외수 침수 등 수재해 발생 빈도 및 피해 규모가 증가하고 있다. 하지만 홍수범람 상황 및 피해양상을 효과적으로 모니터링하고 분석하는 기술은 부족하다. 현재 여러 분야에서 UAV를 활용한 다양한 연구가 진행되고 있다. 그러므로 홍수 모니터링에 UAV를 활용함으로써 홍수 모니터링의 적시성 및 정확성의 향상을 기대할 수 있다. 최근까지도 홍수로 인한 침수에 관한 많은 연구가 이루어지고 있으나 홍수로 인한 배수에 관한 연구는 미흡한 실정이다. 본 연구에서는 UAV 촬영을 통해 취득한 포인트 클라우드 자료를 기반으로 한 경사도 기법을 활용하여 DSM을 하천 측량에 활용 가능한 DEM으로 변환하여 지형자료를 구축하였다. 2차원 수치모형인 FLUMEN을 사용하여 홍수로 인한 침수와 배수를 고려한 모의를 수행 중이며 모의 결과를 UAV 홍수 모니터링 영상과 비교, 검증할 것이다. 또한, 침수와 배수의 소요시간 등을 분석하고 검토할 것이다.

• Korean Journal of Remote Sensing
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• v.16 no.3
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• pp.281-291
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• 2000

In this study tree plantation planning for the plantation blocks of Eucalyptus species was constructed in order to apply to the two farms Jangada and Jamaica, where are located in the western district of the state Mato Grosso do Sul in Brazil. At first the satellite photo was analyzed for the land use classification and the forest ecosystem was classified with GIS technique, and then on the basis of this result the planting available area was accounted for the two farms. According to the request of the land owner the planting planning was established for the planting available area for 3 years. The total area for the two farms is 5,301 ha, and the planting available area is estimated to be 3,913ha(74%). The rest area is 1,388ha(26%), and should be classified to the permanent legal reserve forest area. In order to minimize the soil loss and the erosion, the planting blocks were divided according to the parallel to the contour line： for the first planing year the plantation area was divided to the 27 blocks and the total area was 1,308ha, for the second planing year the area also divided to 27 blocks(1,327.4ha) and for the third planning year 30 blocks divided (1276.5).

• Polymer(Korea)
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• v.31 no.5
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• pp.428-435
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• 2007

The thermomechanical property, morphology, and gas permeability of nanocomposites of ultra high molecular weight polyethylene (UHMWPE) with two different organoclays are compared. Hexamethylene benzimidazole-mica ($C_{16}BIMD-Mica$) and Cloisite 25A were used as reinforcing fillers in the formation of UHMWPE hybrid films. Dispersions of organoclays with UHMWPE were carried out by using the solution intercalation method at different organoclay contents to produce nano-scale composites. Transmission electron microscopy (TEM) micrographs show that some of the clay layers are dispersed homogeneously within the polymer matrix on the nano-scale, although some clay particles are agglomerated. We also found that the addition of only a small amount of organoclay is enough to improve the thermomechanical property and gas barrier of the UHMWPE hybrid films. In general, Cloisite 25A is more effective than $C_{16}BIMD-Mica$ in increasing both the thermomechanical property and the gas barrier in a UHMWPE matrix.

• Polymer(Korea)
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• v.37 no.2
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• pp.225-231
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• 2013

Poly(vinyl alcohol) (PVA) hybrid films containing 5 wt% pristine clay mineral were synthesized in the water solution. The various PVA hybrid films were synthesized from structurally different pristine clays: saponite (SPT), montmorillonite (MMT), hectorite (SWN), hydrophilic bentonite (PGV), and mica (Mica). The thermo-optical properties and morphologies of the PVA hybrid films were evaluated with various pristine clays. The nanostructure of the hybrid films was observed using transmission electron microscopy, which showed that the clay layers were well dispersed into the matrix polymer, although some clusters or agglomerated particles were also detected. The addition of pristine clay was more effective with regard to improving the thermal properties and gas barrier characteristics, whereas the optical transparency of the PVA hybrid films deteriorated with pristine clay.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.12 no.1
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• pp.58-68
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• 1998

A computer-controlled system for measuring dielectric hysteresis has been developed. This system consists of the wave generation par\, the high voltage amplifier part, the measurement part, the data acquisition part and the related controll circuits and is interfaced to P.C(personal computer). The applied voltage and its frequency are controlled by P.C . Since the measured datas can be saved in the RAM of P.C, the analysis and the graphics of the datas are very convenient. As a accuracy test, the capcitances of the commercial mica and styroll capacitors were measured by applying high voltage and the results were good agreement with the rating values. In the test of PZT ceramic sample, the typical D-E hysteresis loops were obtained by applying a single frequency voltage to the sample, and $\varepsilon-E$ and D-E hysteresis loops could be measured at the same time by applying a double frequency voltage to the sample.sample.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.54 no.12
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• pp.561-566
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• 2005

This paper describes electrical resistivity, dielectric strength, thermal conductivity, thermal stability and tensile strength of mica sheet impregnated with silicone rubber resin or silicone rubber resin containing alumina powder. The mica sheet impregnated with silicone rubber resin had higher electrical resistivity, dielectric strength and tensile strength than those of virgin mica sheet. Electrical resistivity of mica sheet impregnated with silicone rubber resin containing alumina increased with increasing the amount of alumina. However, dielectric strength and tensile strength of mica sheet impregnated with silicone rubber resin containing alumina decreased with increasing the amount of alumina. The mica sheet impregnated with silicone rubber resin had lower thermal conductivity than that of virgin mica sheet. However, thermal conductivity of mica sheet impregnated with silicone rubber resin conatining alumina increased with increasing the amount of alumina. In the case of thermal stability, thermal degradation of virgin mica sheet and impregnated mica sheet with silicone rubber resin did not occur up to $1100^{\circ}C$ and $400^{\circ}C$, respectively.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.48 no.2
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• pp.87-95
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• 2022

This study is about the development of transparent cleansing water with one of the beta-hydroxy acids (BHA), salicylic acid, and capryloyl salicylic acid, which is one of the lipo-hydroxy acids (LHA). Transparent appearance was stabilized by increasing the solubility of lipophilic salicylic acid and capryloyl salicylic acid in water using ethanol, polyol, and sodium hydroxide, and supplementing suspension and deposition using a double micelle structure of two types of PEG surfactants. Cleansing water applied with this technology was developed, and makeup removing ability and skin texture improvement ability were confirmed using an optical camera and an image analyzer. This solubilization technology is proposed as a new approach of LHA, which has been difficult to apply due to its low solubility in water, and is expected to help in the development of new chemical peeling products.