• Korean Journal of Ecology and Environment
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• v.39 no.4 s.118
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• pp.489-497
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• 2006

The feasibility of the Natural and Ecological Wastewater treatment System (NEWS) was examined for rural wastewater treatment in Korea. The intermittent trickling biofilter with high hydrophilic filter media was used for pretreatment for suspended solids and organic pollutants. The subsequent constructed wetland with porous granule materials was used for promoting nutrient removal. The results show that the removal efficiencies of the system were high with respect to the water quality parameters except COD. Even if the effluent from the biofilter did not meet the guidelines for wastewater treatment plant effluent in Korea in terms of $BOD_5$ and TN, the final effluent of the system meets the guidelines us to good performance of the constructed wetland. The regression analysis between pollutant loading rate and removal rate indicated that the system could have stable removal for SS, $BOD_5$, TN, and TP in the given influent ranges. The analysis in the winter period indicated that the wetland covered with transparent polycarbonate glass had the statble performance during the winter period dus to increase of temperature inside the wetland without any heating system. With the stable performance, effective poilutant removal, low maintenance, and cost-effectiveness, the NEWS could be considered as an alternative treatment system for decentralized regions and rural communities in Korea.

• Journal of the Korean Society of Food Science and Nutrition
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• v.43 no.12
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• pp.1881-1888
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• 2014

Pre-thermal treatment is important to minimize quality changes during main cooking or storage. In this study, to optimize pre-thermal treatment of carrots, three types of pre-thermal treatments were applied to carrots and quality changes such as physicochemical, nutritional, or sensory properties were observed. Washed and sliced carrots were thermally treated by hot-water immersion ($100^{\circ}C$, 1~10 min), steaming ($100^{\circ}C$, 1~10 min), and stir-frying with oil (10~80 sec). Carrot tissue was maintained until 2 min hot-water immersion or steaming, and they were damaged by just 30 sec of stir-frying. Color and hardness were significantly affected by treatment time and temperature. Color was completely changed after 5 min and 7 min by hot-water and steam treatments, respectively. Hardness decreased to 44% compared with fresh carrot (4,500 g) after 1 min, 3 min, and 20 sec of hot-water, steam, and stir-frying, respectively. For nutritional changes, ascorbic acid, organic acid, and peroxide activity were reduced by all treatments compared with fresh carrot. Especially, succinic acid was dramatically reduced by hot-water treatment. Otherwise, free sugar contents were increased with greater treatment time in all samples. In this study, pre-thermal treatment of carrot was optimal at 2 min steaming treatment.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.58 no.1
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• pp.71-77
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• 2013

The world demand of renewable bioenergy as an alternative transportation fuel is greatly increasing. Research for bioethanol production is currently being progressed intensively throughout the world. Therefore it will be necessary to develop bioethanol production with cellulosic materials. In this study, the yield of ethanol production was evaluated by simultaneous saccharification and fermentation (SSF) using sodium hydroxide pretreated sorghum ${\times}$ sudangrass hybrids. Composition analysis of 11 varieties of sorghum ${\times}$ sudangrass hybrids was performed for selection of excellent variety to efficiently produce bioethanol. The content of cellulose, hemicellulose, lignin and ash of these varieties were 32~39%, 19~24%, 17~22% and 6~11%, respectively. Among these varieties, 4 varieties of sorghum ${\times}$ sudangrass hybrids were selected for the evaluation of ethanol yield and those were pretreated with 1 M NaOH solution at $150^{\circ}C$ for 30 min using high temperature explosion system. After pretreatment, samples were neutralized with tap water. It contained 52~57% of cellulose. Simultaneous saccharification and fermentation (SSF) was carried out for 48 h at $33^{\circ}C$ by Saccharomyces cerevisiae CHY1011 using Green star variety. The yield of ethanol was 92.4% and the amount of ethanol production was estimated at 6206 L/ha.

• Applied Biological Chemistry
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• v.39 no.5
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• pp.384-388
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• 1996

This research was conducted to investigate the effective methods for browning inhibition on yam (Dioscorea aimadeimo) during dehydration by physical and chemical pretreatments. Moisture, crude protein, crude fiber and N-free extract contents of yam were 81.17%, 1.43%, 0.29% and 15.81%, respectively. Yams were sliced to 0.5 cm thickness and placed to single and poly layer in plastic tray, and then changes of their weights were measured during air dehydration at $50^{\circ}C,\;65^{\circ}C,\;and\;80^{\circ}C$. The dehydration time reaching to optimum moisture level for the pulverization of the yam slices were 10, 6, 3 hours(single layered) and 12, 7, 5 hours(multi layered) at the respective temperature. To inhibit browning at $80^{\circ}C$ air dehydration, water and steam blanching, microwave treatment effects were investigated on yam slices for 30 sec. and 60 sec. Steam blanching for 30 sec. was comparatively effective to inhibit browning of yam slices. Yam slices were immersed in single and combined browning inhibitor solutions and evaluated for browing degree during dehydration by the values of Hunter L, a, b and ${\Delta}E$. The most effective pretreatment to inhibit browning of yam slices was immersion In the solution containing 500 ppm of citric acid and 1000 ppm of cysteine for 1 min.

• Journal of Life Science
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• v.13 no.4
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• pp.421-427
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• 2003

A natural habit at bacterium, Enterobacter intermedious KH410 was isolated from freshwater plant root and identified. Adsorption of heavy metals such as lead, cadmium, and copper by this strain was examined. The minimal inhibitory concentrations(MIC) for each metal were 1.78 mM for lead, 0.17 mM for cadmium and 1.39 mM for lopper, respectively. Maximum production of dried cell was 2.56 g/$\ell$ in LB medium containing 0.5% NaCl, 1% yeast extract and 1% of lactose. Optimal conditions for adsorption were 0.6 dry g-biomass, at pH 4.0 and the temperature of $20^{\circ}C$. Adsorption equilibrium reached maximum after 30 min in 400 mg/$\ell$ metal solution. The adsorption capacity (K) of copper was 1.5 times higher than that of cadmium and lead was 1.1 times higher than that of cadmium. from the results obtained in this study, Freundlich adsorption model was applicable for all metals. Adsorption strength (1/n) of heavy metal ions were in the order of cadmium>copper>lead. The adsorption of dried cell for lead, cadmium, and copper was 56.2, 58.0, 55.8 mg/g-biomass, respectively. Pretreatment to increase ion strength was the most effective with 0.1 M NaOH whereas slight difference was found both KOH and $CaCl_2$ upon same concentration. Effective desorption was induced by 0.1 M EDTA for lead and 0.1 M $HNO_2$ for cadmium and copper.

• Korean Journal of Food Science and Technology
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• v.48 no.5
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• pp.461-465
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• 2016

In order to prevent the blackening and texture softening of heated shrimp, the pH was adjusted by soaking shrimps in acidic and alkali solutions, and their qualities were evaluated. The lightness of shrimps pretreated with 0.2% (w/w) citric acid and 0.05% (w/w) ascorbic acid solution increased by 20% compared to that of the control. The strength of mechanical hardness of shrimps soaked in acetic acid and phosphate solution (pH 6.0) was significantly higher ($1209g_f$) compared to that of untreated shrimp ($801g_f$; p<0.05), and the overall preference of texture was 0.4 points higher than that of the control in the descriptive sensory evaluation (p<0.05). In contrast, soaking in solution of pH 8 exhibited a weak texture hardening effect ($855g_f$). Additionally, the hardness of the heated shrimp after soaking at an adjusted pH of 4.0 increased to $4046g_f$, but the yield based on weight decreased to 38% compared to that of untreated shrimp (70%; p<0.05).

• Polymer(Korea)
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• v.34 no.4
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• pp.313-320
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• 2010

New cinnamate group-containing copolymers for a self-curable, humidity-sensitive polyelectrolyte and polymeric anchoring agents were prepared by copolymerization of [2-[(methacryloyloxy) ethyl]dimethyl]propyl ammonium bromide(MEPAB), methyl methacrylate(MMA), 3-(trimethoxysilyl) propyl methacrylate(TMSPM) and 2-(cinnamoyloxy)ethyl methacrylate(CEMA). Photocrosslinkable copolymer composed of MEPAB/MMA/TMSPM/CEMA＝70/20/0/10 were used for humidity-sensitive membrane, and those of 50/0/20/30 and 0/0/50/50 were used for polymeric anchoring agents. 3- (Triethoxysilyl)propyl cinnamate(TESPC) was also used as a surface-pretreating agent for the comparison of capability of attachment of polyelectrolyte to the electrode surface with polymeric photocurable silanecoupling agents. Pretreatment of the electrode substrate with anchoring agents was performed to form a cinnamate thin film on the electrode through covalent bonds. When the sensors were irradiated with UV light, the anchoring of a polyelectrolyte into the substrate was carried out via the [2$\pi$+2$\pi$] cycloaddition. The resulting sensors using polymeric anchoring agents and TESPC showed water durability with increase of resistance by 60~85%, which is corresponding to the reduction of 2.25~3.15%RH, after soaking in water for 24 h. They showed good hysteresis (-0.2%RH), response time (90 sec) and long-term stability at high temperature and humidity.

• Applied Chemistry for Engineering
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• v.32 no.5
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• pp.569-573
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• 2021

In this study, high-density carbon blocks were manufactured using coke, binder pitch, and impregnated pitch, then the effect of pitch fluidity on the densification of carbon blocks during the impregnation process was investigated. A green block was manufactured through high-pressure figuration of coke and binder pitch, and a carbon block was obtained through a heat treatment process. An impregnation process was performed to remove pores generated by volatilization of the binder pitch during the heat treatment process. The impregnation process was carried out the high-pressure reaction step of impregnating the pitch into the carbon block followed by the pretreatment step of melting the impregnation pitch. Melting of the impregnation pitch was carried out at 140~200 ℃, and the viscosity of the impregnation pitch decreased as the heat treatment temperature increased. The decrease in the viscosity of the impregnation pitch improved the fluidity and effectively impregnated the pores inside the carbon block, reducing the porosity of the carbon block by 83% and increasing the apparent density by 5%.

• FLOWER RESEARCH JOURNAL
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• v.26 no.4
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• pp.187-194
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• 2018

This study was conducted to investigate the facilities, cultivation, postharvest management, and distribution status of 27 cut chrysanthemum farms in Korea. The 60% of farms have cultivated the cut chrysanthemum using soil fertigation system in the PE plastic house. In Jeonnam and Busan provinces, Standard type of chrysanthemum was cultivated mainly than spray type of chrysanthemumJeoas. Most farms have been producing the rooted cuttings by plug system using cuttings self-propagated or purchased from the company, but farms in Jeonnam have been planting cuttings directly on cultivation bed. And the 66.6% of cut chrysanthemum farms have been pretreating with dipping in hot water or tap water after harvesting. Precooling was not performed on 70.4% of the farms, and precooling farms have been mainly conducted at temperature of $2-4^{\circ}C$. After harvesting, 70.4% of the farms stored the cut flowers at $2-4^{\circ}C$ for more than 48 hours to control the distribution volume. Cut chrysanthemum was graded mainly by individuals before distribution, and some export farmers have been conducting the cooperative grading. In distribution, all farms have distributed the cut flowers to the domestic markets, and 44.4% of these farms have been also exporting. The 63.0% of farms distributed to domestic market have been trading with flower auction sites.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.33 no.3
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• pp.97-103
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• 2023

Barrier films for transparent packaging materials with excellent moisture barrier properties are prepared, utilizing a nanoclay dispersion coating layer formed after a pretreatment process of plasma activation surface treatment process under vacuum at room temperature. Attention is paid on optimizing the coupling additive through the appropriate crosslinking process and optimal dispersion process of the coating process to enhance adhesion. Analysis of the functional coating thin film shows that the water vapor transmission rate is less than 10 g/m²/24 hrs (ASTM F-1249) and the oxygen transmission rate is less than 30 cc/m²/24 hrs (ASTM D3985). It is shown that water barrier properties of coating thin film prepared in this study are greater than conventional untreated films by 10 times or more. The thickness of the transparent gas barrier film is within 0.1 mm, and the transparent gas barrier complex is implemented in two layers. In the study of PET thin film interface characteristics, FT-IR experimental analysis shows the reaction activity was optimized at RDS 1.125 %.