• Current Research on Agriculture and Life Sciences
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• v.30 no.2
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• pp.82-89
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• 2012

Commercial powdered soups, such as potato soup(PS), corn soup(CS), and chicken-herb soup(CHS), were gamma-irradiated at 0, 1, 5 and 10 kGy and subjected to physicochemical evaluation and identification trials by analyzing photostimulated luminescence(PSL), electron spin resonance(ESR), and thermoluminescence(TL). The changes in moisture content and pH of soup samples were negligible upon irradiation. The Hunter's color determinations showed that lightness (L value) decreased and yellowness (b value) increased as the irradiation dose increased in PS sample. The viscosity of irradiated samples was reduced in the order of PS, CS and CHS. The analyses of PSL, ESR and TL were applicable to the identification of irradiated powdered-soups at more than 1 kGy by detecting PSL photon counts/60 sec(over 5000), radiation-induced multicomponents-ESR signal, and typical TL glow curve at $150-250^{\circ}C$.

• Resources Recycling
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• v.29 no.1
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• pp.25-34
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• 2020

Electrochemical Quartz Crystal microbalance is a tool that is capable of measuring nanogram-scale mass change on electrode surface. When applying alternating voltage to the quartz crystal with metal electrode formed on both sides, a resonant frequency by inverse piezoelectric effect depends on its thickness. The resonant frequency changes sensitively by mass change on its electrode surface; frequency increase with metal dissolution and decrease with metal deposition on the electrode surface. The relationship between resonant frequency and mass change is shown by Sauerbrey equation so that the mass change during metal dissolution can be measured in real time. Especially, it is effective in the case of reaction mechanism and rate studies accompanied by precipitation, volatilization, compound formation, etc. resulting in difficulties on ex-situ AA or ICP analysis. However, it should be carefully considered during EQCM experiments that temperature, viscosity, and hydraulic pressure of solution, and stress and surface roughness can affect on the resonant frequency. Application of EQCM was shown as a case study on leaching of platinum using aqueous chlorine for obtaining activation energy. A platinum electrode of quartz crystal oscillator with 1000 Å thickness exposed to solution was used as leaching sample. Electrogenerated chlorine as oxidant was purged and its concentration was controlled in hydrochloric acid solution. From the experimental results, platinum dissolution by chlorine is chemical reaction control with activation energy of 83.5 kJ/mol.

• Journal of the Korean Society of Food Science and Nutrition
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• v.26 no.4
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• pp.588-594
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• 1997

In this study, the shelf-life of Kochujang during storage was predicted through physicochemical and sensory analyses. Amino nitrogen, lightness, characteristics of surface color, pH and number of viable cell counts in Kochujang decreased during storage, while ammonia nitrogen, titratable acidity and viscosity increased. Among the physicochemical analyses, amino nitrogen content exhibited the highest correlation with sensory score. The marginal amounts of amino nitrogen was 170.6mg%. Degradation rate of amino nitrogen was a first order reaction. Q$_{10}$-value and the activation energy of Kochujang during storage were 1.80 and 8.6kca1/mol, respectively. The shelf-life Predicted of Kochujang at each storage temperature was calculated. The shelf-life predicted was 467 days at 1$0^{\circ}C$, 261 days at 2$0^{\circ}C$ and 133 days at 35$^{\circ}C$.

• Journal of the Korean Society of Food Science and Nutrition
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• v.36 no.1
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• pp.93-99
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• 2007

The study was carried out to prepare spaghetti sauce with oyster (SSO) and the food components characteristics of the SSO were also compared to those of commercial spaghetti sauces (CSS). The optimal addition ratio of oyster for preparing SSO was 11% based on 100 g of SSO according to the results of organic acid content, Hunter color value, viscosity, and sensory evaluation. The reasonable $F_0$ value for the keeping storage of SSO was about 4 min. The proximate composition of SSO prepared under the optimal processing condition was 71.2% moisture, 2.8% protein, 6.9% crude lipid, and 3.2% crude ash. The results of sensory evaluation suggested that the quality of SSO was superior to that of CSS. However, there was no significant difference (p<0.05) in sensory evaluation on color between CSS and SSO. The total amino acid content (2,532.2 mg/100 g) of SSO was higher than that of CCS (2,305.7 mg/100 g). The contents of calcium and phosphorus of SSO were 25.7 mg/100 g and 48.7 mg/100 g, respectively. The calcium content/phosphorus content showed a suitable ratio for absorbing calcium. The total free amino content and the taste value were 1,040.2 mg/100 g and 151.26, respectively. The major taste-active amino acids were glutamic acid and aspartic acid.

• Journal of the Korean Society of Food Science and Nutrition
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• v.36 no.1
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• pp.72-80
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• 2007

This study was carried out to investigate the effects of various salts on the physical and fermentative characteristics of doughs and on the quality of white pan breads produced using purified salt, Korean solar salt, Chinese solar salt, Mexican solar salt, washed and dehydrated salt, roasted salt, and bamboo salt. In farinogram patterns, dough prepared using the purified salt had the highest water absorption. Extensograms showed that the resistances and resistance/extensibility ratios of the doughs with the solar salts were higher than those with the purified salt. In amylograms, the dough with the bamboo salt had the highest viscosity value. A specific volume was the smallest in the bread with the Korean solar salt (4.11 mL/g), while the largest with the Mexican solar salt (4.85 mL/g). A baking loss rate of the bread prepared with the Korean solar salt (10.34%) was less compared to other samples (10.91 $\sim$ 11.65%). The crust of the bread added with the Korean solar salt showed higher L value and lower a value while its crumb showed the highest b value. A sensory evaluation indicated that significant differences in some characteristics of the breads were observed in the breads prepared with the Korean solar salt and Mexican solar salt. However, flavor, taste, and overall acceptability showed no significant differences among all breads prepared with different salts.

• Journal of the Korean Society of Food Science and Nutrition
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• v.44 no.1
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• pp.118-127
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• 2015

In this study, chiffon cakes were prepared with wild grape powder. Different amounts of the wild grape powder were tested (3%, 6%, 9%, and 12%) to determine the optimal amount. Rice chiffon cake was evaluated for quality characteristics, antioxidant properties, and sensory evaluation. The specific gravity of control batter was 0.48 g/mL, and it decreased with increasing amounts of wild grape powder, whereas viscosity showed the reverse effect. The pH of batter and cake decreased with increasing amounts of wild grape powder. The moisture content significantly increased with increasing amounts of wild grape powder, and the water activity of cakes was not significantly different between samples from 0.905~0.908. For color, lightness and yellowness deceased with increasing amounts of wild grape powder, whereas redness showed the reverse effect. For texture, hardness, fracturability, gumminess, and chewiness significantly increased with increasing amounts of wild grape powder. Total polyphenol content, DPPH radical scavenging activity, and ABTS radical scavenging activity significantly increased with increasing amounts of wild grape powder. In the sensory evaluation, the control sample showed the highest scores for color, flavor, softness, and overall acceptability. Based on these results, wild grape powder could be considered as a functional material, and 6% wild grape powder is the optimum level for manufacture of rice chiffon cake.

• Bulletin of the Korean Chemical Society
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• v.7 no.2
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• pp.137-142
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• 1986

The luminescence spectra of $Ru(bpy)_3^{2+}$ in poly(methacrylic acid) (PMA) solutions varied sensitively with pH. At pH < 5.5, the emission intensity increased with pH up to 4 times, while it decreased with pH beyond the pH. The enhanced emission intensity was accompanied by blue-shift of the emission maxima as much as 15 nm. The enhancement of emission intensity was attributed to the restricted rotational mobility of ligand of the cation bound to densely coiled PMA molecules at pH < 5.5. The sharp decrease in emission intensity with increasing pH near pH 5.6 was accounted for conformational transition of the polymer to more extended structure, which was also revealed in viscosity measurement. The enhancement of emission intensity became higher as NaCl concentration of the solution increased. The binding constant of $Ru(bpy)_3^{2+}$ with two carboxylate groups of PMA was calculated as $2{\times}10^5\;M^{-1}$ in 0.1 M NaCl at pH 5.2. The pH dependence of luminescence quenching rate of $Ru(bpy)_3^{2+}$ by $Cu^{++}$ also showed maximum near pH 5, and the rate was more than $10^3$ times higher than that in water, whereas the maximum enhancement of quenching rate (about 20 times) in poly(acrylic acid) (PAA) solution occurred at pH 4.5. On the other hand, the pH dependence for neutral water soluble nitrobenzene (NB) exhibited opposite trend to that of $Cu^{++}$. The quenching constant vs pH curve for $MV^{++}$ was composite of those for $Cu^{++}$ and NB. The anomalous high quenching rate for $Cu^{++}$ in PMA solution at pH < 5.5 was attributed to the binding of $Ru(bpy)_3^{2+}$ and $Cu^{++}$ to the same region of PMA, when it conforms densely coiled structure in the pH range. The observation of mininium quenching rate for NB near pH 5.5 indicated that the $Ru(bpy)_3^{2+}$ bound to the densely coiled PMA is not accessible by NB, which is in bulk water phase. The composite nature of the pH dependence of quenching rate for $MV^{++}$ in PMA solution was attributed to the smaller binding affinity of the cation to PMA, compared to that of $Cu^{++}$. The sharp, cooperative conformational transition with pH observed in PMA was not revealed in PAA. But, the pH dependence of quenching rates in this polymer reflected increased charge density and, thus, binding of cations to the polymer, and expansion of the polymer chain with pH.

• Korean Journal of Remote Sensing
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• v.26 no.5
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• pp.497-510
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• 2010

In this study, comparisons of the backscattering coefficients and the coherence values which had been extracted from SAR (Synthetic Aperture Radar) images such as JERS-1, ENVISAT and ALOS satellites with surface roughness, surface geometric and soil moisture content were carried out. As the results of analysis using the backscattering coefficient and coherence values from SAR images, the coherence was shown high in the region containing more of mud fraction due to higher viscosity of fine grain-size. A lot of tidal channels were well developed in the Ganghwa tidal flat, affecting the drainage of seawater and subsequent soil moisture content by exposure time of tidal flat. The backscattering coefficient. consequently, appeared to be lower in sand flat and mix flat with decrease of soil moisture. In contrast, most mud flats were distributed at high elevation so that soil moisture was not much influenced by seawater. The backscattering coefficient in mud flat seemed to have a relationship with the density of tidal channel. In addition, lowering backscattering coefficients in the all Ganghwa tidal flat was observed when surface remnant water increased according to the amount of rainfall. The correlation between backscattering coefficient, coherence and sediment environment factors in the Ganghwa tidal flat was investigated. In the future, more quantitative spatial analysis will be helpful to well understand the sedimentary influence of various sediment environment factors.

• Applied Chemistry for Engineering
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• v.30 no.5
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• pp.597-605
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• 2019

In order to improve the adhesion of water-based adhesive, gemini type nonionic reactive surfactants were synthesized and applied to water-based adhesives. The surfactants were synthesized by using maleic acid and polyoxyethylene cetyl ether having different length of ethylene oxide and confirmed by FT-IR and $^1H-NMR$. Their appearance was light yellow wax. The cloud point of the compound was more than $78^{\circ}C$. The measured critical micelle concentration (c.m.c) was $1.0{\times}10^{-4}{\sim}7.0{\times}10^{-4}mol/L$ and surface tension at c.m.c was 25.9~32.0 mN/m. As the number of ethylene oxide increased, the emulsifying power was improved. The foaming height of each compound by Ross-Miles method was 1.4~4.5 cm. The synthesized surfactants was then used as an emulsifier in emulsion polymerization of water-based adhesives and its physical properties were evaluated. The solid contents of prepared adhesives was 59%. The average particle size and initial tackiness of the prepared adhesives were 164~297 nm and ball no. of 20~32, respectively. The peel strength was $1.8{\sim}2.1kg_f/mm$. The retention rate of adhesives viscosity was evaluated to 99% during 30 days. Therefore, synthesized gemini type nonionic reactive surfactants are expected to be applied as an emulsifier for the high adhesive force.

• Proceedings of the Korea Water Resources Association Conference
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• 2018.05a
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• pp.71-71
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• 2018

Sea pollution accidents have been occurred due to the increase of marine ship traffic. Oil spill from the hull hole induced by tanker collision results in the huge sea pollution. Proper and prompt reaction on such oil spill disaster is needed to minimize the damage. Thru-hull emergency wood plug is typically used to manually close small holes, while it is required to develop some mechanical devices for closing large holes in the hull due to huge fluid pressure. Accurate estimation of oil discharge and velocity from such holes are important to develop proper device to control hull hole damage. High resolution CFD modeling investigation on the configurations of hull hole of 7.5 m initial depth and 30 cm diameter, which was observed in the oil spill accident of the Hebei Sprit off the west coast of Korea in 2007, has been carried out to compute the oil spill velocity distribution in terms of flow depth. Friction loss due to the viscous flow and the discharge coefficient of crude oil with specific gravity SG = 0.85 and viscosity of $4-12cP(mPa{\cdot}s)$ at the temperature of $20^{\circ}C-100^{\circ}C$ are presented in terms of Reynolds number based on the results of high-resolution CFD modeling.