• 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 Institute of Electrical and Electronic Material Engineers
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• v.18 no.6
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• pp.582-586
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• 2005

We have grown GaN layers with in-situ SiN mask by metal organic chemical vapor deposition (MOCVD) and study the physical properties of the GaN layer. We have also investigate the effect of the SiN mask on its optical property. By inserting a SiN mask, (102) the full width at half maximum (FWHM) decreased from 480 arcsec to 409 arcsec and threading dislocation (TD) density decreased from $3.21\times10^9\;cm^{-2}\;to\;9.7\times10^8\;cm^{-2}$. The PL intensity of GaN with SiN mask improved 2 times to that without SiN mask. We have thus shown that the SiN mask improved significantly the physical and optical properties of the GaN layer.

• Elastomers and Composites
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• v.29 no.5
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• pp.436-443
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• 1994

Melamine resin was mixed with polybutadiene rubber or wood flour in the ranges of $5{\sim}75%(wt.%)$. For mixtures, physical and thermal properties were tested experimentally. Physical properties were mainly influenced on the dispersed states of rubber or wood flour. The highest flexural and impact strength were obtained at wood flour content $65{\times}67%$. Rubber was homopolymerized by hardner, or partially copolymerized with melamine resin. At rubber content $3{\sim}6%$, cured products represented lower modulus without decreasing mechanical strength.

• Proceedings of the Korea Concrete Institute Conference
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• 2004.05a
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• pp.604-607
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• 2004

Concrete structures in the marine environment often deteriorate in the early stage of their service life because of contact with various aggressive conditions. In recent years, the study on the concrete in the marine environment are carried out to increase their service life. In this experimental study, the concrete specimens were prepared with various adding contents of inorganic antifouling agent$(0\~3.0wt\%)$ composed to some fluosilicate solution. For evaluatin of the physical and chemical properties of concretes containing inorganic antifouling agent, various tests such as setting time, slump loss, compressive strength, water absorption rate, freezing and thawing resistance and SEM micrographs of concrete, were conducted. As the results, physical and chemical properties of concretes were improved with an adding of inorganic antifouling agent. From the results of various tests, the optimal adding contents of antifouling agent was $1.0wt\%$.

• Proceedings of the Korean Geotechical Society Conference
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• 1999.11c
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• pp.39-55
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• 1999

Geotextile composites to improve the weather ability were composed of recycled polyester geotextile with carbon black as ultraviolet stabilizer and polypropylene geotextile by needle-punching method, and evaluated physical properties, ultraviolet resistance and chemical stability. Retention ratio of tensile properties of non woven polypropylene geotextiles were decreased about 50% by the exposed condition with ultraviolet but those of geotextile composites were slightly decreased than polypropylene geotextiles. Geotextile composites which have larger weights of polyester geotextile were more stable against ultraviolet. For chemical stability, the changes of tensile properties of geotextile composites were in the range of -20~＋10% at the various chemical conditions.

• Korean Journal of Soil Science and Fertilizer
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• v.37 no.3
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• pp.143-148
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• 2004

Organic and inorganic substrates commonly used in Korea include peat moss, coir, bark, rice hull, saw dust, perlite, vermiculite, rockwool granulate, clay ball, and so on. The objective of this study was to get analytical results about the physical and chemical properties of these substrates by European standard methods. Organic substrates showed different properties depending on the type, origin and manufacturing processes. Inorganic substrates showed different properties depending on the type and particle size. Further study on physical and chemical properties for more raw materials and commercially available growing media analyzed by European standard method and comparison of the results with those by Korean standard method is needed.

• Journal of Electrochemical Science and Technology
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• v.12 no.3
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• pp.297-301
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• 2021

Microbial fuel cells (MFCs) convert chemical energy to electrical energy via electrochemically active microorganisms. The interactions between microbes and the surface of a carbon electrode play a vital role in capturing the respiratory electrons from bacteria. Therefore, improvements in the electrochemical and physicochemical properties of carbon materials are essential for increasing performance. In this study, a microwave and sulfuric acid treatment was used to modify the surface structure of graphite granules. The prepared expandable graphite granules (EGG) exhibited a 1.5 times higher power density than the unmodified graphite granules (1400 vs. 900 mW/m³). Scanning electron microscopy and Fourier transform infrared spectroscopy revealed improved physical and chemical characteristics of the EGG surface. These results suggest that physical and chemical surface modification using sulfuric acid and microwave heating improves the performance of electrode-based bioprocesses, such as MFCs.

• Journal of the Korean Applied Science and Technology
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• v.24 no.1
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• pp.10-22
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• 2007

To prepare weather-resistant silicone/acrylic resin coatings for an architectural purpose, tetrapolymers were synthesized by a radical polymerization. 3-Methacryloxypropyltrimethoxysilane (MPTS) as a silicone monomer and n-butyl acrylate, methyl methacrylate, and n-butyl methacrylate as acrylic monomers were used. The compositions of monomers were adjusted to fix the glass transition temperature of acrylic polymer for $20^{\circ}C$. The composition of MPTS in the synthesized polymer were varied from 10 wt% to 30 wt%. On the basis of synthesized resin amber paints were prepared and their physical properties and effects for weatherability were examined. The presence of MPTS in silicone/acrylic resins generally resulted in low molecular weight and broad molecular weight distribution, and also lowered the viscosity of the copolymers. The coated films prepared from these resins showed good and balanced properties in general. Adhesion to the substrate was outstanding in particular. Weatherability tests were carried out in three different types such as outdoor exposure, QUV, and SWO. The test results showed that the silicone/acrylic resins containing 30 wt% of MPTS had weather-resistant properties.

• 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 Korea institute for structural maintenance and inspection
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• v.16 no.4
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• pp.44-51
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• 2012

In this study, hardened loess bodies, which did not compose of cement or any chemical binder, were made and tested to evaluate the physical properties such as slump, air content, and compressive strength. Addition of a natural binding material to mixture of loess and lime showed better performance in physical properties. However a lime among natural binding materials is considered as a superior binder to improve the properties of the hardened bodies. According to the experimental results, mixing proportion with 45% of W/B ratio, $285kg/m^3$ of water content, and 60% lime substitution ratio was recommended to acquire the good performance of physical properties for the hardened loess bodies.