• The Korean Journal of Quaternary Research
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• v.21 no.2
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• pp.19-22
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• 2007

• Bulletin of the Korean Chemical Society
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• v.33 no.5
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• pp.1759-1761
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• 2012

• Journal of the Korean Regional Science Association
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• v.11 no.1
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• pp.93-111
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• 1995

This study investigated the nature of spatial concentration and dispersion of corporate control within an international system of decision-making centers. It introduces a simplified model of the global evolution of quaternary places. Linked to the national quaternary place model, the proposed model is useful for examinations involving real world situations associated with international corporations. This five stage model emphasizes the importance of the organizational structure of large corporations, industrial networks and the development of information technology. It suggests the dispersion of international quaternary places along with the diversification of corporate control linkages among quaternary centers. A case study for 1974-1991 uses information statistics to identify the current stage of the international quaternary system. The result is in general agreement with major elements of the stage model. This theoretical concept and empirical research contribute to the expansion of quaternary place theory to the global scale in particular, and to the development of location analysis in general.

• Proceedings of the IEEK Conference
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• 2003.07c
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• pp.2621-2624
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• 2003

In this paper, we designed 12Bit DAC(Digital to Analog Converter) that applied to multiple-valued logic system to Binary system. The proposed D/A Converter structure consists of the Binary to Quaternary Converter(BQC) and Quaternary to Analog Converter(QAC). The BQC converts the two input binary signals to the one Digit Quaternary output signal. The QAC converts the Quaternary input signal to the Analog output signal. The proposed DAC structure can implement voltage mode DAC that high resolution low power consumption with reduced chip area. And also, it has advantage of the easy expansion of resolution and fast settling time.

• Elastomers and Composites
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• v.51 no.3
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• pp.188-194
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• 2016

In this study, novel quaternary plastomers consisting of ethylene, 1-hexene, high ${\alpha}$-olefin, and divinylbenzene were prepared using Zr metallocene catalyst, borate type cocatalyst, and tri-isobutylaluminium. The molar ratio changes of 1-hexene and high ${\alpha}$-olefin (1-octene, 1-decene, and 1-dodecene) had an effect on the properties of the quaternary plastomers. The structure of the quaternary plastomers was characterized using $^1H$ NMR. Molecular weight properties, crystallinity, and thermal properties of the plastomers were determined by GPC, WAXS, and DMA, respectively. Compared with the terpolymers prepared in our previous study, molecular weight and molecular weight distribution of the quaternary polymers were very similar, whereas glass transition temperature ($T_g$) was very low. Also, hardness and tensile properties of the quaternary plastomers were measured.

• Bulletin of the Korean Chemical Society
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• v.25 no.7
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• pp.1095-1098
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• 2004

• The Korean Journal of Quaternary Research
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• v.19 no.2
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• pp.18-20
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• 2005

• Journal of Ginseng Research
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• v.13 no.2
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• pp.189-197
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• 1989

A new quaternary ammonium compound, hydrolyzed ginseng-saponin quaternary (HGSQ), from Korean ginseng saponin and 2,3-epoxypropyltrimethylammonium chloride has been developed as a conditioning agent in cosmetics. This structure has a hydrophobic group from the aglycone of ginseng saponin which is biologically active and considered to be the most important component of the Korean ginseng. Its properties : surface tension, critical micelle concentration (CMC), eye irritation, sorption onto hair, force reduction(%) and moisture retention effect were studied. Its cationic character allows the molecule to be more substantive than ginseng saponin. HGSQ had good physical properties and was safe. enough as a cosmetic raw material. Also half-head tests of HGSQ-containing shampoo were carried out to compare the conditioning effects in shampoos. HGSQ was an excellent conditioning agent in shampoo..

• Journal of the Korean Chemical Society
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• v.56 no.4
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• pp.464-467
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• 2012

A novel chitosan derivative with double quaternary ammonium salt-2-pyridine-acetyl-N-trimethyl chitosan chloride (PATMCS) was synthesized and the antioxidant activity of PATMCS against hydroxyl radicals was assessed. The results indicated that PATMCS had potent hydroxyl scavenging activity. The $IC_{50}$ of PATMCS was 0.13 mg/mL. PATMCS showed 100% scavenging effect at a dose of 0.8 mg/mL which markedly better than that of N-trimethyl chitosan chloride (TMCS). It was confirmed that quaternary chitosan derivatives showed potent antioxidant activity. PATMCS has double quaternary ammonium salt structure in the molecules. Therefore, the antioxidant activity of PATMCS was better than TMCS. The above results are theoretically fundamental for further development and making use of chitosan resources to prepare new antioxidants.

• Bulletin of the Korean Chemical Society
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• v.30 no.6
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• pp.1379-1382
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• 2009