• Korean Journal of Medicinal Crop Science
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• v.28 no.1
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• pp.47-55
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• 2020

Background: Curcuma longa L., a perennial crop originating from tropical and subtropical region, including India, is noted for its important medicinal properties. However, C. longa plants are unable to endure the winter season in Korea, and its rhizomes were invariably succumb to fungal infection when stored in polyvinyl bags. In this study, we accordingly sought to develop a C. longa variety capable of producing high rhizome yields and to identify stable conditions under which rhizomes can be stored in Korea. Methods and Results: We evaluated the agronomic characteristics of nine C. longa germplasms and examined the effects of storing rhizomes at different temperatures (4℃ to 24℃) in paper bags or plastic baskets. We found that the finger rhizomes was higher in CUR02, CUR03, and CUR06 germplasms than those of other groups. Furthermore, in terms of yield per 1 ㎡, the weights of the finger rhizomes and tuberous roots were significantly higher in CUR09 (3.4 ㎏/㎡) and CUR04 (678.7 g/㎡) than those of other groups. Therefore, we consider that these C. longa germplasms might be useful as breeding material. Although the fresh weights of the rhizomes were slightly reduced when stored in paper bags and a plastic baskets at 10℃ to 15℃, there was no evidence of fungal decomposition or sprouting, which is observed when using a conventional storage method. Conclusions: The results of this study indicate that the selected C. longa germplasms can provide a useful source of breeding material for the development of high yielding varieties and that a temperature ranging from 10℃ to 15℃ and the use of paper bags or plastic baskets provide stable post-harvest storage conditions for C. longa rhizomes.

• Journal of Marine Bioscience and Biotechnology
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• v.9 no.2
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• pp.35-42
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• 2017

Hydrothermal liquefaction of lipid-extracted Tetraselmis sp. feedstock containing 80 wt.% water was conducted in a batch reactor at different temperatures (300, 325, and $350^{\circ}C$) and reaction times (5, 10, 20, 40, and 60 min). The biocrude yield, elemental composition and higher heating value obtained at various reaction conditions were used to predict the optimum conditions for maximizing energy recovery of biocrude with good quality. A maximum energy recovery of 67.6% was obtained at $325^{\circ}C$ and 40 min with a high energy density of 31.8 MJ/kg and lower contents of nitrogen and oxygen. Results showed that reaction conditions of $325^{\circ}C$, 40 min was most suitable for maximizing energy recovery while at the same time achieving improved quality of biocrude.

• Journal of Korean Society of Water and Wastewater
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• v.32 no.4
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• pp.357-361
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• 2018

Forward osmosis (FO) process has been attracting attention for its potential applications such as industrial wastewater treatment, wastewater reclamation and seawater desalination. Particularly, in terms of fouling reversibility and operating energy consumption, the FO process is assumed to be preferable to the reverse osmosis (RO) process. Despite these advantages, there is a difficulty in the empirical step due to the lack of separation and recovery techniques of the draw solution. Therefore, rather than using FO alone, recent developments of the FO process have adapted a hybrid system without draw solution separation/recovery systems, such as the FO-RO osmotic dilution system. In this study, we investigated the performance of the hollow fiber FO module according to various operating conditions. The change of permeate flow rate according to the flow rates of the draw and feed solutions in the process operation is a factor that increases the permeate flow rate, one of the performance factors in the positive osmosis process. Our results reveal that flow rates of draw and feed solutions affect the membrane performance, such as the water flux and the reverse solute flux. Moreover, use of hydraulic pressure on the feed side was shown to yield slightly higher flux than the case without applied pressure. Thus, optimizing the operating conditions is important in the hollow fiber FO system.

• Advances in concrete construction
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• v.9 no.6
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• pp.547-556
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• 2020

This study aimed to develop reference materials (RMs) that are chemically stable and can simulate the flow characteristics of cement paste. To this end, the candidate components of RMs were selected considering the currently required properties of RMs. Limestone, slag, silica, and kaolin were selected as substitutes for cement, while glycerol and corn syrup were selected as matrix fluids. Moreover, distilled water was used for mixing. To select the combinations of materials that meet all the required properties of RMs, flow characteristics were first analyzed. The results revealed that silica and kaolin exhibited bilateral nonlinearity. When an analysis was conducted over time, slag exhibited chemical reactions, including strength development. Moreover, fungi were observed in all mixtures with corn syrup. On the other hand, the combination of limestone, glycerol, and water exhibited a performance that met all the required properties of RMs. Thus, limestone, glycerol, and water were selected as the components of the RMs. When the influence of each component of the RMs on flow characteristics was analyzed, it was found that limestone affects the yield value, while the ratio of water and glycerol affects the plastic viscosity. Based on this, it was possible to select the mixing ratios for the RMs that can simulate the flow characteristics of cement paste under each mixing ratio. This relationship was established as an equation, which was verified under various mixing ratios. Finally, when the flow characteristics were analyzed under various temperature conditions, cement paste and the RMs exhibited similar tendencies in terms of flow characteristics. This indicated that the combinations of the selected materials could be used as RMs that can simulate the flow characteristics of cement paste with constant quality under various mixing ratio conditions and construction environment conditions.

• Journal of the Korean Society of Food Science and Nutrition
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• v.31 no.3
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• pp.405-410
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• 2002

The optimum conditions of the alcohol fermentation with raw tapioca by simultaneous saccharification and alcohol fermentation (SSAF) were studied using raw starch enzyme. The optimum conditions for maximum alcohol production were 0.5% (w/w) of enzyme content, 250% (v/w) of added water content and 96 hr of fermentation time. The alcohol and reducing sugar contents were 11.7% and 306 mg% after 96 hr fermentation, respectively. During the fermentation pH decreased from 6.2 to 4.2 and total acidity increased from 0.11 to 0.43. Alcohol components were detected such as ethanol, methanol, iso-propanol, n-propylalcohol and iso-butylalcohol, besides acetaldehyde. We could construct raw starch fermentation conditions which was 250% (v/w) of added water content and 0.5% (w/w) of enzyme content. However, yield of raw starch alcohol fermentation was lower than that of steaming alcohol fermentation.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.45 no.1
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• pp.20-25
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• 2000

Viviparous germination causes yield loss and quality deterioration of rice. This study was conducted to investigate varietal differences of the viviparous germination with different days after heading (DAH) and different temperatures. In the laboratory examination, the averaged germination rate of all varieties at 45DAH and at 25DAH was 79.9%, and 27.5% under the incubation at the temperature of 3$0^{\circ}C$/2$0^{\circ}C$ (day/night) for 12 days. Andabyeo, Da- sanbyeo, and Nonganbyeo showed the lowest viviparous germination rates among the tested varieties. The shoot length of the viviparous germination measured 12days after incubation at 30/2$0^{\circ}C$ ranged from 21 to 53mm, indicating significant deterioration of rice quality. In the field test, the averaged viviparous germination rates of rice varieties at 25, 35, 45DAH with the underwater conditions for 4 days were 2.2, 6.2 and 9.2%, respectively, while their rates at 12 day after underwater conditions increased to 17.6, 44.2 and 43.8%, respectively. A variety that showed the highest viviparous germination rate at 25 and 35 and 45DAH was Heukjinjubyeo. When standing rice panicles without lodging were examined after consecutive raining for 7 days Juanbyeo showed the highest viviparous germination (45.5%), followed by Odaebyeo (16.0%), Jinbubyeo (14.5 %), Bongkwangbyeo (14.2 %) and Obongbyeo (12.6%). The viviparous germination of rice was greatly affected by variety, days after heading and temperature settings. Bongkwangbyeo, Juanbyeo, Dongjinbyeo, Hwasunchalbyeo, Naepoongbyeo and Heukjinjubyeo were classified as the most susceptible varieties to the viviparous germination in the field conditions.

• Journal of Microbiology and Biotechnology
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• v.18 no.1
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• pp.110-117
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• 2008

Three kinds of prenylated flavonols, icariside I, icariside II, and icaritin, were isolated from an icariin hydrolysate and their effects on melanogenesis evaluated based on mushroom tyrosinase inhibition and quantifying the melanin contents in melanocytes. Although none of the compounds had an effect on tyrosinase activity, icariside II and icaritin both effectively inhibited the melanin contents with an $IC_{50}$ of 10.53 and $11.13{\mu}M$, respectively. Whereas icariside II was obtained from a reaction with ${\beta}$-glucosidase and cellulase, the icariin was not completely converted into icariside II. Thus, for the high-purity production of icariside II, the reaction was optimized using the response surface methodology, where an enzyme concentration of 5.0mg/ml, pH 7, $37.5^{\circ}C$, and 8 h reaction time were selected as the central conditions for the central composite design (CCD) for the enzymatic hydrolysis of icariin into icariside II using cellulase. Empirical models were developed to describe the relationships between the operating factors and the response (icariside II yield). A statistical analysis indicated that all four factors had a significant effect (p<0.01) on the icariside II production. The coefficient of determination $(R^2)$ was good for the model (0.9853), and the optimum production conditions for icariside II was an enzyme concentration of 7.5mg/ml, pH 5, $50^{\circ}C$, and 12 h reaction time. A good agreement between the predicted and experimental data under the designed optimal conditions confirmed the usefulness of the model. A laboratory pilot scale was also successful.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.18 no.3
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• pp.13-22
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• 2015

Unpaved forest roads are common accessways in mountain areas being used for forestry purposes. The presence of forest roads produces large volumes of surface runoff and sediment yield due to changes in soil properties and hillslope profile. Rainfall simulation experiments were conducted to estimate the impacts of above-ground vegetation and antecedent soil water condition on hydrology and sediment processes. A total of 9 small plots($1m{\times}0.5m$) were installed to represent different road surface conditions: no-vegetation(3 plots), vegetated surface(3 plots), and cleared vegetation surface(3 plots). Experiments were carried out on dry, wet, and very wet soil moisture conditions for each plot. Above ground parts of vegetation on road surface influenced significantly on surface runoff. Runoff from no-vegetation roads(39.24L) was greater than that from vegetated(25.05L), while cleared-vegetation condition is similar to no-vegetation roads(39.72L). Runoff rate responded in a similar way to runoff volume. Soil erosion was also controlled by land cover, but the magnitude is little than that of surface runoff. Even though slight differences among antecedent soil moisture conditions were found on both runoff and soil erosion, runoff rate and soil losses were increased in very wet condition, followed by wet condition. The experiments suggest that vegetation cover on forest road surface seems most effective way to reduce surface runoff and soil erosion during storm periods.

• Journal of the Korean Society of Tobacco Science
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• v.23 no.2
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• pp.109-114
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• 2001

A CAB cDNA vector(pKGCAB), encoding the light harvesting chlorophyll a/b binding protein in Korean ginseng (Panax ginseng C. A. Meyer), was constructed with the CaMV35S promoter of plant expression vector. The chimeric vector was transformed into tobacco(Nicotiana tabacum cv. NC 82) using Agrobacterium tumefaciens LBA 4404 strain, and the transgenic tobacco plant CAB-TP2 was selected. Photosynthetic rates of the CAB-TP2 plant at before-flowering stage were increased about 20% under low irradiance conditions of quantum 100 and 500 $\mu$mol.m$^{-2}$ s$^{-1}$ , however, the rates were similar to those of NC 82 under quantum 1000 and 2000 $\mu$mol.m$^{-2}$ s$^{-1}$ conditions. The plants were germinating under low- or normal irradiance condition and the quantum yield of photosystem III were measured. The differences of the Fv/Em values between conditions were 0.07 and 0.01 in NC 82 and CAB-TP2, respectively. The mature leaves in the position 8-10 of the CAB-TP2 at before-flowering stage revealed l0% higher Fv/Fm values in range of 0.759 to 0.781 and 40% more chlorophyll contents of 70-93mg/$m\ell$ than those of normal NC 82. These data suggest the possibility that the increase in photosynthetic activity of leaves under low light intensity in the canopy of CAB-TP2 transgenic tobacco might lead to increase the quality of lower tobacco leaves.

• Applied Chemistry for Engineering
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• v.20 no.2
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• pp.186-190
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• 2009

This study is purposed to analyze thermodynamic properties on the hydrogen production by dimethyl ether steam reforming. Various reaction conditions of temperatures (300~1500 K), feed compositions (steam/carbon = 1~7), and pressures (1, 5, 10 atm) were applied to investigate the effects of the reaction conditions on the thermodynamic properties of dimethyl ether steam reforming. An endothermic steam reforming competed with an exothermic water gas shift reaction and an exothermic methanation within the applied reaction condition. Hydrogen production was initiated at the temperature of 400 K and the production rate was promoted at temperatures exceeding 550 K. An increase of steam to carbon ratio (S/C) in feed mixture over 1.5 resulted in the increase of the water gas shift reaction, which lowered the formation of carbon monoxide. The maximum hydrogen yield with minimizing loss of thermodynamic conversion efficiency was achieved at the reaction conditions of a temperature of 900 K and a steam to carbon ratio of 3.0.