• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.8 no.1
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• pp.150-157
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• 1999

In this study, the loader was completed that has 4-wheel gear driven drivetrain of study (Ⅰ), the 4-wheel steering with power wheel type, all-wheel traction system, and joy-stick type lever for hydraulic control valve. From driving test of the developed 4WD and 4WS type loader, we obtained that the minimum circling radius and the necessary width in circling motion reduced about 40% and 33% compared with 2WS type loader. Also, all-wheel traction system could keep the tires glued to the ground with greater stability, the power steering allowed a smoother operation, and the joy-stick type lever offered easily to control. Thus, the developed loader having these functions was very fit in a small cattle shed or rugged ground.

• Natural Product Sciences
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• v.19 no.3
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• pp.201-205
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• 2013

Thirteen phenolic compounds, 1,4-dimethoxybenzene (1), 3,4-dihydroxybenzaldehyde (2), (2E)-3-(4-hydroxy-3,5-dimethoxyphenyl)acrylaldehyde (3), 3,7-dihydroxy-4H-chromen-4-one (4), 2,3-dihydroxy-1-(3,4-dihydroxyphenyl)propan-1-one (5), 4-hydroxy-3-methoxybenzoic acid (6), 4-hydroxy-3,5-dimethoxybenzoic acid (7), methyl 3,4-dihydroxybenzoate (8), 4-hydroxy-3,5-dimethoxybenzaldehyde (9), 3,4-dihydroxybenzoic acid (10), 3-hydroxy-1-(4-hydroxy-3-methoxyphenyl)propan-1-one (11), 2,4,6-trihydroxybenzaldehyde (12) and benzene-1,2,4-triol (13) were isolated from the heartwood of Caesalpinia sappan. Their anti-inflammatory activity was evaluated against LPS-induced NO production in macrophage RAW264.7 cells. Among them, compounds 3 and 8 showed strong inhibitory activities toward the LPS-induced NO production in macrophage RAW264.7 cells with $IC_{50}$ values of 14.5 and 21.5 ${\mu}M$, respectively.

• Journal of the Korean Chemical Society
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• v.41 no.2
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• pp.82-87
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• 1997

The 1,4-bis(alkyldichlorosilyl)benzene was synthesized to be a precursor of the bis(silacyclopentadienyl) aromatic system. The cyclization reaction of the precursor with 1,4-dilithio-1,2,3,4-tetraphenyl-1,3-butadiene produced the 1,4-bis(1'-alkyl-2',3',4',5'-tetraphenyl-1'-silacyclopentadienyl)benzene as the ligand of organotransition metal compound and the precursor of the stable silacyclopentadienyl anion.

• YAKHAK HOEJI
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• v.44 no.4
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• pp.325-333
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• 2000

The 1,3-dipolar cycloaddition reaction of the quinoxaline 4-oxides 2 with 2-chloroacrylonitrile gave the 2,3-dihydro-1H-1,2-diazepino[3,4-b]quinoxalines 3, which were converted into the 2,3,4,6-tetrahydro-1H-1,2-diazepino[3,4-b]quinoxalines 5-7. The reaction of compounds 3 with selenium dioxide in acetic acid/water resulted in ring transformation to give the 1,4-dihydro-4-oxopyridazino[3,4-b]quinoxalines 8.

• Bulletin of the Korean Chemical Society
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• v.19 no.2
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• pp.178-183
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• 1998

Carbon-13 CP-MAS NMR techniques were used to investigate dynamics of new combined type liquid crystalline polymers, poly[oxy-1,4-phenyleneoxy-2-{6-(4-(4-butylphenylazo)phenoxy)hexyloxy}terephthaloyl] and poly[oxy-1,4-phenyleneoxy-2-{10-(4-(4-butylphenylazo)phenoxy)decyloxy}terephthaloyl]. Noticeable mobility change of either aromatic groups or methylene groups is not detected between 25 ℃ and 82 ℃ from 13C spinlattice relaxation time in the rotating frame (T1ρ(C)) and contact time array experiments. However, line shape analysis shows the increase of mobility of methylene carbons in poly[oxy-1,4-phenyleneoxy-2-{6-(4-(4-butylphenylazo)phenoxy)hexyloxy}terephthaloyl] at higher temperature. The dynamics of side chanis does not seem to be affected in our experimental temperature range by the length of aliphatic chain which is connecting the side chain group to the main chain.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.24 no.4
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• pp.140-144
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• 2014

Co-(0.7 wt%) and Pr-(2.0, 3.5 or 5.0 wt%) doped cubic zirconia ($ZrO_2:Y_2O_3=50:50wt%$) single crystals grown by a skull melting method were heat-treated in $N_2$ at $1150^{\circ}C$ for 5 hrs. The brown colored as-grown single crystals were changed into either dark brownish green, greenish blue and light green color after the heat treatment. Before and after the heat treatment, the YSZ (yttria-stabilized zirconia) single crystals were cut for wafer form (${\phi}7.5mm{\times}t3mm$). The optical and structural properties were examined by UV-VIS spectrophotometer and X-ray diffraction. Absorption by $Co^{2+}$(${\fallingdotseq}589nm$: ${\Gamma}_8[^4A_2(^4F)]{\rightarrow}{\Gamma}_8+{\Gamma}_7[^4T_1(^4F)]$, ${\fallingdotseq}610nm$: ${\Gamma}_8[^4A_2(^4F)]{\rightarrow}{\Gamma}_8[^4T_1(^4F)]$], ${\fallingdotseq}661nm$: ${\Gamma}_8[^4A_2(^4F)]{\rightarrow}{\Gamma}_6[^4T_1(^4F)]$]) and $Pr^{3+}$(${\fallingdotseq}450nm$: ${^3}H{_4}-{^3}P{_2}$, ${\fallingdotseq}473nm$: ${^3}H{_4}{\rightarrow}{^3}P{_1}$, ${\fallingdotseq}484nm$: ${^3}H{_4}{\rightarrow}{^3}P{_0}$), change of ionization energy and lattice parameter were confirmed.

• Journal of Broadcast Engineering
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• v.15 no.6
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• pp.815-829
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• 2010

In this paper, we propose a new $4{\times}4$ intra coding method by unidirectional prediction for improvement of intra-frame coding efficiency of H.264/AVC. There are $4{\times}4$, $8{\times}8$, and $16{\times}16$ intra prediction modes in the current H.264/AVC. For the $4{\times}4$ intra prediction, coding efficiency is achieved by accurate prediction with small block size in relatively complicated regions, and the $16{\times}16$ intra prediction method can predict more accurately compared to $4{\times}4$ intra prediction with only one directional information in relatively homogeneous regions. We propose a unidirectional $4{\times}4$ intra prediction method adopting a small-size prediction and one directional prediction approaches. In order to improve coding efficiency, the proposed method is conducted by $4{\times}4$ block and their prediction directions are all the same, resulting that we need to send only one directional information for each macroblock. For intra-frame coding setting, we achieve 10.47% and 1.57% coding efficiency in BD-bitrate for only $16{\times}16$ intra mode and $4{\times}4$, $16{\times}16$ intra mode, respectively.

• Korean Security Journal
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• no.53
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• pp.137-157
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• 2017

The purpose of this study was to analyze similarity on types of illegal weapon self-report such as firearms, swords, shells, bullets, explosives in 16 regions of Korea in 2011, 2015. The results of this study were as follows. First, the types of illegal weapon self-report in 2011 were divided into two clusters, such as (1) 'cluster 1' including firearms, swords, shells and explosives, (2) 'cluster 2' including bullets. Second, the multidimensional scales on the types of illegal weapon self-report in 2011 were firearms located in the lower right corner(4/4), swords located in the lower right corner(4/4), shells located in the lower right corner(4/4), bullets located in the center left corner(3/4), explosives located in the higher right corner(1/4). Third, the types of illegal weapon self-report in 2015 were divided into two clusters, such as (1) 'cluster 1' including firearms, swords, shells and explosives, (2) 'cluster 2' including bullets. Forth, the multidimensional scales on the types of illegal weapon self-report in 2015 were firearms located in the lower right corner(4/4), swords located in the higher right corner(1/4), shells located in the higher right corner(1/4), bullets located in the center left corner(2/4), explosives located in the center right corner(4/4).

• Journal of the Korean Society of Food Science and Nutrition
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• v.30 no.4
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• pp.623-629
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• 2001

This study was investigated the quality characteristics of sponge cakes which were prepared b replacing 30% of flour with raw starch and resistant starches, such as, 4 cycled autoclaved-cooled RS 3 maize starch(RS 3), cross-linked RS 4 maize starch (RS 4) was superior to control cake( 100% flour cake). Addition of starches except RS 3 made crust and crumb color lighter and decreased hardness. Especially, cake containing RS 4 had the softest texture. For the adhesiveness and cohesiveness, cake containing RS 4 showed the least changes during 5 storage days. In DSC measurement, cakes containing RS 4 and ARS 4 showed high enthalpy in despite of low hardness. Sensory evaluation showed that cakes containing RS 4 and ARS 4 were significantly moist and soft compared to others. Overall acceptability of cakes containing starch, RS 4 and ARS 4 were evaluated excellent. Therefore, it can be suggested that RS 4 and ARS 4 can be added to the sponge cake for the quality improvement and functional element.

• Tribology and Lubricants
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• v.18 no.4
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• pp.267-272
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• 2002

Nano adhesion between SPM(scanning probe microscope) tips and DDPO$_4$(octadecylphosphoric acid ester.) and ODPO$_4$(octadecylphosphoric acid ester) SAM(self-assembled monolayer.) was experimentally studied. Tests were performed to measure the nano adhesion and friction in both AFM(atomic force microscope) and LFM(lateral force microscope) modes with the applied normal load. DDPO$_4$ and ODPO$_4$ SAM were formed on Ti and TiOx surfaces. Ti and TiOx were coated on the Si wafer by ion sputtering. Adhesion and friction of DDPO$_4$ and ODPO$_4$ SAM surfaces were compared with those of OTS(octadecyltrichlorosilane) SAM and DLC surfaces. DDPO$_4$ and ODPO$_4$ SAM converted the Ti and TiOx surfaces to be hydrophobic. When the surface was hydrophobic, the adhesion and friction forces were found lower than those of bare surfaces. Work of adhesion was also discussed to explain how the surface was converted into hydrophobic Results also showed that tribological characteristics of DDPO$_4$ and ODPO$_4$ SAM had good properties in the adhesion, friction, wetting angle and work of adhesion. DDPO$_4$ and ODPO$_4$ SAM could be one of the candidates for the bio-MEMS elements.