• Membrane and Water Treatment
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• v.1 no.3
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• pp.207-214
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• 2010

Approximately 80% of water used in urban areas reappears as municipal wastewater (MWW). Reclamation of MWW is an attractive proposition under the present scenario of water stressed cities in India. In this paper, we attempted to reclaim MWW using lab-scale hollow- fiber (HF) membrane modules for possible reuse in non-potable applications. Experiments were conducted to evaluate the efficiency of virgin HF ($M_1$) and modified HF ($M_2$) modules. The $M_2$ module consists of HF modified with a skin layer formed through interfacial polymerization of m-phenylenediamine with trimesoyl chloride (MPD-TMC). The molecular weight cut-off (MWCO) of $M_1$ was 44000 g/mol and that of $M_2$ 10000 -14000 g/mol on the basis of rejection of polyethylene glycol. The combination of $M_1$ and $M_2$ modules was able to reduce concentrations of most of the pollutants in sewage and improved the treated water quality to the acceptable limits for non potable reuse applications. It is found that about 98-99% of the initial flux is recovered by the backwashing process, which was approximately two times in a month when operated continuously.

• Journal of Korean Society on Water Environment
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• v.22 no.1
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• pp.1-6
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• 2006

In this study, five commercially available fouling resistant low-pressure RO membranes were investigated for the treatment of seasonally brackish surface water with high organic content (${\approx}24mg/L$). The membranes investigated are LFC-1 (Hydranautics), X20 (Trisep), BW30FR1 (FilmTec), SG (Osmonics), and BE-FR (Saehan). The results of surface characterization revealed that each of these membranes has one or two unique surface characteristics to minimize the adherence of the fouling materials to the membrane. Specifically, the LFC1 membrane features a neutral or low negative surface to minimize electrostatic interactions with charged foulants. The X20, on the other hand, shows a highly negatively charged surface, and thus, is expected to perform well with feed waters containing negatively charged organics and colloids. The BW30FR1 exhibits a relatively neutral and hydrophilic surface, which could be beneficial for lessening organic and/or biofouling. The SG membrane has a smooth surface that makes it quite resistant to fouling, particularly for colloidal deposition. Lastly, BE-FR membrane demonstrated a medium surface charge and a slightly higher hydrophobicity. In the pilot study, all of the four membranes experienced a gradual increase in MTC (water mass transfer coefficient or specific flux) over time, indicating no fouling occurred during the pilot study. The deterioration of permeate water quality such as TDS was also observed over time, suggesting that the integrity of the membranes was compromised by the monochloramine used for biofouling control.

• The Korean Journal of Food And Nutrition
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• v.31 no.4
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• pp.502-510
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• 2018

To begin with, this study identified and reviewed the proximate compositions, quality and physicochemical characteristics of three Korean cowpea (Vigna unguiculata L. Walp.) cultivars grown in two different seedling periods. The proximate compositions of the cowpea showed significant differences according to three cultivars (Seowon, Yeonboon and Okdang) and two different seeding periods (5 June and 5 July). Through this lens, the lightness, redness and yellowness of the cowpea cultivars increased slightly during the 5 July cultivation compared to the 5 June cultivation. This brings us to understand that the water binding capacity, water solubility index, and swelling power were significantly different among the cultivars. In this case, the water binding capacity of the cowpea was 108.87~143.19%, and decreased during the 5 July cultivation compared to the 5 June cultivation. As shown, the total polyphenol and flavonoid contents of cowpea showed significant difference according to cultivars. In this case, the total polyphenol content of 5 June and 5 July cultivation on the Seowon 4.17 and 4.12 mg GAE/g, respectively. In these terms, the DPPH radical scavenging activity of cowpea showed a significant difference according to the cultivars, and the Yeonboon and Okdang increased slightly during 5 July cultivation. The ABTS radical scavenging activity of the cowpea showed significant difference according to the cultivars, and all cultivars decreased slightly during the 5 July cultivation. In other words, the phenol contents and radical scavenging activity differ measurable depending on the cultivars and seeding periods. Therefore, it is necessary to study the proper cultivar and seeding time considering the environment of the applicable cultivation area.

• Journal of the Korean Society of Marine Environment & Safety
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• v.29 no.3
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• pp.255-269
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• 2023

Surface water temperature of a bay (from the south to the north) increases in spring and summer, but decreases in autumn and winter. Due to shallow water depth, freshwater outflow, and weak current, the water temperature in the central to northern part of the bay is greatly affected by the land coast and air temperature, with large fluctuations. Water temperature variations are large in the north-east coast of the bay, but small in the south-west coast. The difference between water temperature and air temperature is greater in winter and in the south-central part of the bay than that in the north to the eastern coast of the bay where sea dykes are located. As the bay goes from south to north, the range of water temperature fluctuation and the phase show increases. When fresh water is released from the sea dike, the surrounding water temperature decreases and then rises, or rises and then falls. The first mode of empirical orthogonal function (EOF) represents seasonal variation of water temperature. The second mode represents the variability of water temperature gradient in east-west and north-south directions of the bay. In the first mode, the maximum and the minimum are shown in autumn and summer, respectively, consistent with seasonal distribution of surface water temperature variance. In the second mode, phases of the coast of Seosan~Boryeong and the east coast of Anmyeon Island are opposite to each other, bordering the center of the deep bay. Periodic fluctuation of the first mode time coefficient dominates in the one-day and half-day cycle. Its daily fluctuation pattern is similar to air temperature variation. Sea conditions and topographical characteristics excluding air temperature are factors contributing to the variation of the second mode time coefficient.

• Korean Journal of Medicinal Crop Science
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• v.14 no.4
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• pp.212-216
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• 2006

Root of Scutellaria baicalensis G. was extracted with methanol and water to give the yield of 30.0% in order to find the antioxidant substance. The extract was fractionated with diethyl ether, n-butanol and water to test the inhibitive activity against xanthine oxidase. Three fractions inhibited the activities of xanthine oxidase by 48.2%, 10.2% and 2.8%, respectively, at the amount of $0.1\;{\mu}g$. A component that exhibited strong inhibition of xanthine oxidase was isolated from diethyl ether fraction (SE Fr.) by silica gel column chromatography and HPLC, and then identified by $^1H-NMR$, $^{13}C-NMR$ and MS spectrophotometry. EDA (Electron Donating ability) of the compound was 28.5% at the concentration $100\;{\mu}g/3\;ml$. That was identified to be 3,5,7-trihydroxy-2'-methoxyflavanone by spectrophotometric analysis using $^1H-NMR,\;^{13}C-NMR$ and Mass spectrophotometry.

• Korean Journal of Ichthyology
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• v.23 no.2
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• pp.150-157
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• 2011

In this study we described reproduction study of Korean endemic species, Acheilognathus koreensis and three other acheilognathinae species A. signifer, Rhodeus pseudosericeus, and R. uyekii. Morphology of egg shape and larvae just hatched is unique by the species respectively. There is no interrelation factor between size of female and number of spawned eggs per one time. Minium water temperature for spawning of A. koreensis was observed in $13.0^{\circ}C$ having low hatching rate with 43.5 percent. The egg of A. koreensis began to hatch approximately 79 hours after insemination. As higher as water temperature until $22.0^{\circ}C$ hatching elapsed time for developing eggs of A. koreensis and three species in this study was shortened. A. koreensis was grew up to be a adult enough which can be join to new production for three hundred days after hatching with 52.4 mm in total length. This reproduction study will be applied to preservation of Korean endemic fresh water fishes basically.

• The Korean Journal of Food And Nutrition
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• v.34 no.4
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• pp.381-389
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• 2021

Saengcheonggukjang, known as Natto in Japan, is a soybean fermented food which is made from steamed soybean, Bacillus and water. Demand of Saengcheonggukjang has increased because it does not have much smell compared to Cheonggukjang. Seven varieties of Saengcheonggukjang were investigated and compared in terms of 100 seed weight, quality characteristics, hard seed rate, and water absorption rate in order to determine the suitability of Korean soybeans. In addition, each characteristic of Saengcheonggukjang was compared. 'Hoseo' and 'Haewon' showed low 100 seed weight with 8.41 g and 8.11 g, respectively. The water absorption rate was higher in 'Hoseo' and 'Pungwon' than in Japan varieties. The yield of Saengcheonggukjang was significantly different for each variety. No differences were observed in yield and hardness of Saengcheonggukjang with respect to the varieties and sowing date. 'Haewon' showed the highest amino nitrogen content with 575.0 mg%. Viscous material content did not appear to differ between varieties. These results suggested that 'Hoseo' and 'Haewon' can be considered as suitable candidates for yield and quality of Saengcheonggukjang compared to Japan varieties.

• The Korean Journal of Food And Nutrition
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• v.31 no.5
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• pp.577-586
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• 2018

The proximate compositions, quality and physicochemical characteristics of mung-bean cultivars cultivated in the north-central region of South Korea with different seeding periods were evaluated. A significant difference was noted in the proximate compositions and chromaticity of mung-beans according to cultivars and different seeding periods. Crude ash and protein content decreased with the delay in seeding period and a slight increase in carbohydrate content was observed. Redness of the other five cultivars increased with the delay in seeding period except for the cultivar Jangan, while the yellowness decreased in cultivars Geumsung and Jangan. Water binding capacity of the $1^{st}$, $2^{nd}$ and $3^{rd}$ seeding on the cultivar Eoul was 115.15, 99.76 and 96.31%, respectively, and a decrease in the binding capacity was observed with the delay in seeding periods. Water solubility index and swelling power were significantly different among cultivars. Total polyphenol content of $1^{st}$ and $2^{nd}$ seeding on the cultivar Jangan was 8.59 and 8.57 mg GAE/g, respectively, and a decrease was observed with the delay in seeding periods except for the cultivar Sohyeon. Total flavonoid content of $1^{st}$ seeding on the cultivar Jangan was 5.25 mg CE/g, which decreased with the delay in seeding periods. DPPH radical scavenging activity of $1^{st}$ seeding on the cultivars Geumsung and Kyungseon was 2.44 and 2.32 mg TE/g, respectively, which decreased with the delay in seeding periods. The BTS radical scavenging activity of $1^{st}$ seeding on the cultivar Jangan was 6.98 mg TE/g. In the present study, the variations in phenol content and radical scavenging activity were observed to be dependent on the cultivars and seeding periods.

• Membrane and Water Treatment
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• v.8 no.6
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• pp.613-623
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• 2017

We report the novel thin film composite RO membrane modified by graphene oxide. The thin film composite RO membrane was exposed to 2000 mg/l sodium hypochloride; thereafter it was subjected to different graphene oxide concentration ranging from 50 mg/l to 1000 mg/l in water. The resultant membrane was crosslinked with 5000 mg/l N-hydroxysuccinimide. The performance of different membranes were analysed by solute rejection and water-flux measurement. It was found that 100 mg/l graphene oxide exposure followed by 5000 mg/l N-hydroxysuccinimide treatment resulted in the membrane with the highest solute rejection of 97.78% and water-flux of 4.64 Liter per sqm per hour per bar g. The membranes were characterized by contact angle for hydrophilicity, scanning electron micrographs for surface morphology, energy dispersive X-Ray for chemical composition of the surface, Atomic force microscope for surface roughness, ATR-FTIR for chemical structure identification. It was found that the graphene oxide modified membrane increases the salt rejection performance after exposure to high-fouling water containing albumin. Highly hydrophilic, antifouling surface formation with the nanomaterial led to the improved membrane performance. Moreover, the protocol of incorporating nanomaterial by this post-treatment is simple and can be applied to any RO membrane after it is manufactured.

• Korean Chemical Engineering Research
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• v.53 no.2
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• pp.199-204
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• 2015

Response surface methodology (RSM) in combination with a 17-run central composite design (CCD) was applied to optimize the non-catalytic hydrolysis of lard using subcritical water to produce fatty acids (FA). The effects of three variables including temperature, molar ratio of water to oil and time, and their relationship on FA content were investigated. A quadratic regression model was employed to predict the FA contents. Optimum reaction conditions for maximizing the FA content were obtained as follows: reaction temperature of $288.5^{\circ}C$, molar ratio of water to oil of 39.5 and reaction time of 29.5 min. Under the optimum conditions, the predicted and experimentally obtained FA contents were 97.06% and 96.99%, respectively.