• Bulletin of the Korean Chemical Society
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• v.30 no.1
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• pp.124-128
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• 2009

In this study, the effect of multi-step purification or functionalization on physicochemical properties of multi-walled carbon nanotubes (MWNTs)/epoxy (EP) nanocomposites was investigated. The nanocomposites containing multi-step purified MWNTs showed a stronger influence on $T_g$ and increased in mechanical properties in comparison to nanocomposites containing the same amount of only purified MWNTs. Consequently, the multi-step purification of MWNTs led to an improvement of thermomechanical properties of nanocomposites, resulting from improving the intermolecular interaction of MWNTs in epoxy matrix resins.

• Bulletin of the Korean Chemical Society
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• v.33 no.3
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• pp.855-861
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• 2012

A pioneering version of an on-line management system for high-energy molecules (MS-HEMs) was developed by the ADD and BMDRC in Korea. The current system can manage the physicochemical and explosive properties of virtual and existing HEMs. The on-line MS-HEMs consist of three main routines: management, calculation, and search. The management routine contains a user-friendly interface to store and manage molecular structures and other properties of the new HEMs. The calculation routine automatically calculates a number of compositional and topological molecular descriptors when a new HEM is stored in the MS-HEMs. Physical properties, such as the heat of formation and density, can also be calculated using group additivity methods. In addition, the calculation routine for the impact sensitivity can be used to obtain the safety nature of new HEMs. The impact sensitivity was estimated in a knowledge-based manner using in-house neural network code. The search routine enables general users to find an exact HEM and its properties by sketching a 2D chemical structure, or to retrieve HEMs and their properties by giving a range of properties. These on-line MS-HEMs are expected be powerful tool for deriving novel promising HEMs.

• Journal of the Korean Chemical Society
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• v.58 no.5
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• pp.500-503
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• 2014

• Bulletin of the Korean Chemical Society
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• v.34 no.11
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• pp.3481-3484
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• 2013

• Bulletin of the Korean Chemical Society
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• v.29 no.9
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• pp.1678-1684
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• 2008

• Bulletin of the Korean Chemical Society
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• v.22 no.1
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• pp.107-109
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• 2001

• Analytical Science and Technology
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• v.30 no.4
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• pp.213-219
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• 2017

Polyalkylsiloxane has been spotlighted in pressure-sensitive adhesive (PSA) application due to excellent physical properties and good biocompatibility. Thermal behaviour of polyalkylsiloxane mixtures, such as thermal stability and heat flow, were studied using TG-DTA during catalytic hydrosilation. To understand reaction kinetics of cross-linking, catalytic hydrosilation of polyalkylsiloxane was monitored using variable temperature nuclear magnetic resonance (VT-NMR) as increased temperature. The formation of cross-linking bond $Si-CH_2-CH_2-Si$ was directly observed using distortionless enhanced by polarization transfer (DEPT) technique. Successfully polyalkylsiloxane PSA samples exhibited excellent adhesion properties by cross-linking reaction.

• Journal of the East Asian Society of Dietary Life
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• v.14 no.2
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• pp.135-144
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• 2004

A total of 40 Korean and Japanese rice varieties were evaluated for their main chemical components, physical properties, cooking quality, pasting properties, and instrumental measurements. Based on their quality evaluations, it was concluded that Korean and Japanese rice varieties were not significantly different in the basic components of NIR (Near Infra Red) data and the chemical analysis from the uncooked brown and milled rices. Korean rice had a little bit higher protein and amylose contents but much lower fat acidity than those of Japanese rice from the chemical analysis. From all the data of three different kinds of NIR methods, Korean and Japanese milled rice were very similar except the taste score. Japanese rice showed a slightly higher taste score, a little bit higher lightness and whiteness, but lower yellowness and redness than Korean one. From all those data of NIR and the chemical analysis, Korean and Japanese rices had very similar components except the fat content.

• Journal of the Korean Society of Tobacco Science
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• v.22 no.2
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• pp.133-137
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• 2000

The bulk curing experiment to improve the quality of flue-cured leaves were carried out to evaluate relationship between the modified(3 step-up) drying and conventional drying method in bulk curing process. Modified drying method was somewhat higher values in yellowing color index of cured leaves, and less brittle than those in conventional drying program. As to the chemical properties, there was no difference in chemical component levels in cured leaves between the modified and the conventional methods, while the major chemical compounds in relation to aromatic essential oil of cured leaves showed mostly higher level in the modified method than that in conventional drying method. Additionally 3 step-up drying method increased the tobacco quality by 2 % in price per kg compared with conventional drying method.

• Elastomers and Composites
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• v.55 no.1
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• pp.1-5
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• 2020

This study examined the effects of the addition of maleic anhydride-grafted polypropylene (PP-g-MA) and polyolefin elastomer (POE) on polyamide 66 (PA66) and polypropylene (PP) blends. The blends of PA66/PP with PP-g-MA and POE were prepared using a twin screw extruder. Mechanical testing results revealed that the tensile, flexural, and izod impact strengths of the blends were maximized at a PP-g-MA content of 2 phr. The increased mechanical strength of the blends with PP-g-MA was attributed to the compatibilizing effect of the PA66 and PP blends. In addition, as the POE content increased, the impact strength of the blends increased. However, at a high POE content, the tensile and flexural strengths decreased, seemingly because of the lower mechanical properties of POE.