• Journal of the Korean Applied Science and Technology
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• v.36 no.1
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• pp.324-332
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• 2019

Most countries including Korea and Indonesia have strong policy for implementing biofuels like biodiesel. Shortage of the oil feedstock is the main barrier for increasing the supply of biodiesel fuel. In this study, in order to improve the stability of feedstock supply and lower the biodiesel production cost, the feasibility of biodiesel production using two types of Indonesian tropical crop oils, pressed at different harvesting times, were investigated. R. Trisperma oils, a high productive non-edible feedstocks, were investigated to produce biodiesel by esterification and transesterification because of it's high impurity and free fatty acid contents. the kindly provided oils from Indonesia were required to perform the filtering and water removal process to increase the efficiency of the esterificaton and transesterification reactions. The esterification used heterogeneous acid catalyst, Amberlyst-15. Before the reaction, the acid value of two types oil were 41, 17 mg KOH/g respectively. After the pre-esterification reaction, the acid value of oils were 3.7, 1.8 mg KOH/g respectively, the conversions were about 90%. Free fatty acid content was reduced to below 2%. Afterwards, the transesterification was performed using KOH as the base catalyst for transesterification. The prepared biodiesel showed about 93% of FAME content, and the total glycerol content was 0.43%. It did not meet the quality specification(FAME 96.5% and Total glycerol 0.24%) since the tested oils were identified to have a uncommon fatty acid, generally not found in vegetable oils, ${\alpha}$-eleostearic acid with much contents of 10.7~33.4%. So, it is required to perform the further research on reaction optimization and product purification to meet the fuel quality standards. So if the biodiesel production technology using un-utilized non-edible feedstock oils is successfully developed, stable supply of the feedstock for biodiesel production may be possible in the future.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.24 no.1
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• pp.128-138
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• 2019

Effects of feeding type and food resource availability on community structure of mollusks inhabiting hard-bottom subtidal areas were investigated. By following guidance from several references, mollusks observed in this study were divided into 5 groups according to feeding type - 1) grazing, 2) filter feeding, 3) deposit feeding, 4) omnivorous and 5) predation. The results showed that both grazing and filter feeders were the most numerous, explaining grazing type in the East Sea accounting for 47.9%, 32.6% in the South Sea and 29.6% for filter feeding, and filter feeding as a dominant feeding type in Yellow Sea accounting for 42.3%. Results of this study showed distinctive difference in community structure depending on mechanism of feeding type and geographical areas where sampling took place. With the results, attempts were made to understand whether community structure could be affected by feeding type or feeding availability and found out that community structure depended heavily on food resource availability. In the East Sea where marine algal density was high, the algal community in the forms of thick-leathery and sheet often occurred in water column with high transparency which provides proper environment for growth. In the South Sea where grazing and filter feeding types were predominated similarly, the algal density was high, but had the relative highest phytoplankton density. Whereas in the Yellow Sea showing the lowest algal biomass compared to the one in the East and the South Sea, and phytoplankton density was similar to those. It might be a adequate environment for filter feeders than grazers. This study concluded that community structure of mollusks showing high abundance was present where food resource availability with types and quantity was high.

• Applied Chemistry for Engineering
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• v.30 no.2
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• pp.226-232
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• 2019

The biological wastewater treatment is more eco-friendly and can be used effectively in wastewater for a variety of purposes than that of the conventional treatment. In particular, the wastewater treatment using microalgae in biological treatment processes has attracted great attention due to its ability to remove economically nutrients from wastewater and have many advantages as a renewable energy source. This study was investigated to establish the optimal growth conditions for microalga Scenedesmus obliquus. Additionally, the removal efficiencies of nutrients (N, P) and heavy metals (Cu, Zn) from the synthetic wastewater were evaluated. As a results, the optimal growth conditions were established at $28^{\circ}C$, pH 7, and light and dark cycle of 14 : 10 h. In the evaluation of nutrient removal efficiencies at each concentrations of 500, 1,000, 5,000, and 10,000 mg/L, the removal rates were 17.6~70% N and 8.4~34% P in the single treatment and 12.0~58.0% N and 3.0~40.3% P in the binary mixture treatment. In addition, the evaluation of heavy metal removal efficiencies at each concentrations of 10, 30 and 50 mg/L, the removal rates were 13.7~40.3% Cu and 10.0~30.0% Zn in the single treatment and 16.0~40.0% Cu and 12.0~20.0% Zn in the binary mixture treatment. Based on the results of the study, it appears that Scenedesmus obliquus can be used for the removal of nutrients and heavy metals from the swine wastewater.

• Korean Journal of Breeding Science
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• v.50 no.4
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• pp.472-477
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• 2018

"Hyangcheola" is a new japonica rice variety developed as a cross between "Joryeong" and "Seolhyangchal" by the rice breeding team at NICS in 2014. The heading date of "Hyangcheola" is July 28 in the middle plain area, which is 8 days earlier than that of "Hwaseong." "Hyangcheola" has a 76 cm long culm, which is 8 cm shorter than "Hwaseong" and has 86 spikelets per panicle. The viviparous germination rate of "Hyangcheola" was 27.9%. It showed resistance to stripe virus but susceptibility to bacterial blight (K1, K2, and K3 races), dwarf and black streak dwarf viruses and planthoppers. The milled rice of this variety exhibits translucent and medium short grain shape. The protein content of "Hyangcheola" was 8.2%, which was 1.5% higher than that of "Hwaseong." "Hyangcheola" is a rice with a fragrant aroma. The content of iron in 100 g of brown "Hyangcheola" rice was 15.12 mg, which is 3.69 mg higher than that of "Hwaseong," and the zinc content was 32.24 mg, which is 8.75 mg more than that of the comparative variety "Hwaseong." The average milled rice yield of "Hyangcheola" was 4.8 MT/ha at our sites under ordinary cultivation (Registration No. 6807).

• Korean Journal of Breeding Science
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• v.50 no.4
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• pp.490-496
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• 2018

"Samkwang1," a japonica rice variety, was developed as a cross between "Samkwang" and F1 of Suwon152 (IT008283), which has a medium maturing and lodging resistance and Samkwang (IT284608), a high quality variety with bacterial blight resistance and mid-late maturing property by the rice breeding team at NICS in 2015. The heading date of "Samkwang1" was August 8 in the middle plain area, which was 2 days early than that of "Hwaseong." "Samkwang1" had a culm length of 77 cm, which was 7 cm shorter than that of "Hwaseong," and it had 128 spikelets per panicle. The viviparous germination rate of "Samkwang1" was 2.1%. "Samkwang1" showed resistance to blast, bacterial blight (K1, K2, and K3 race) and stripe virus, but was susceptible to the K3a race of bacterial blight, dwarf and black streak dwarf viruses, and plant hoppers. The milled rice of this variety exhibits translucent and medium short grains. The cooked rice grains of "Samkwang1" have an excellent palatability index (0.35) and lower protein content (6.2%) than that of "Hwaseong." The characteristics related to grain milling were better than those of "Hwaseong," especially the head rice milling recovery ratio and head rice ratio (94.2%). "Samkwang1" showed 5.62 MT/ha of milled rice productivity at 11 sites under ordinary cultivation conditions (Registration No. 6798).

• Applied Chemistry for Engineering
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• v.31 no.6
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• pp.612-623
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• 2020

This study was initiated to quantitatively evaluate the inhibitory effects of five heavy metals (Cd, Cu, Zn, Pb, Ni) on bacterial growth and phosphorus removal in the binary culture of Alcaligenes sp. plus Pseudomonas sp. IC50 values of Alcaligenes sp. plus Pseudomonas sp. for Cd, Cu, Zn, Pb, and Ni were 0.75, 10.93, 7.08, 13.30, and 15.78 mg/L, respectively. For the binary treatments of heavy metals, IC50 was the lowest in the treatment of Cd + Cu, whereas, it was the highest in the Ni + Pb treatment. The EC50 values for Cd, Cu, Zn, Pb, and Ni were 0.54, 11.08, 6.14, 9.33, and 13.81 mg/L, respectively. For the binary treatments of heavy metals, EC50 was the lowest in the Cd + Zn, whereas, the highest in the Zn + Ni. Based on both IC50 and EC50 values for the binary culture of bacteria with the binary mixtures of heavy metals, the most interactive effect was found to be antagonistic, though the only synergistic effect was found in Cu + Ni treatment. Therefore, our results can provide basic data on the toxic effects of heavy metals on the bacterial growth and phosphorus removal in the wastewater treatment process.

• Korean Journal of Agricultural and Forest Meteorology
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• v.22 no.4
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• pp.258-267
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• 2020

The agrivoltaic can produce electricity and grow crops on fields at the same time. It is necessary to analyze the cultivation environment and evaluate the crop productivity under agrivoltaic because the shading point changes according to structure of agrivoltaic and sun's position. Two types of "fixing" and "tracing" agrivoltaic were installed, and a rice cultivation experiment was conducted in the fields under each agrivoltaic and without shading (control). "Hyunpoombyeo" was transplanted on June 7, 2019, and grown with fertilization of 9.0-4.5-5.7 kg/10a (N-P-K). Fifteen weather stations were installed under each agrivoltaic to measure solar radiation and temperature, and yield and yield-related elements were investigated by points. The accumulated solar radiation during the rice growing season in fixing was no much difference between points, and that in tracing was much difference between points. However, the average solar radiations of two agrivoltaics were similar. The mean temperature, yield, and yield-related elements showed a significant difference for the shading rate, and decreased with increasing the shading rate except ripening grain rate and 1000 grain weight of fixing agrivoltaic. In the relationship between shading rate and yield, fixing and tracing were fitted to a logistic equation and a simple linear equation, respectively, and showed a high correlation (tracing: R2 = 0.62, fixing: R2 = 0.73). The shading rate variation by point for two types was large despite similar yield variation. Thus, it needs to be more closely examined the relationship of the shading rate for a specific period rather than the shading rate during the whole growing season.

• Korean Journal of Food Science and Technology
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• v.53 no.1
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• pp.46-54
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• 2021

The biological activities of non-edible extracts of asparagus stems and roots were investigated using hot water and ethanol. The highest contents of rutin and total polyphenol were 31.74 mg/g and 20.14 mg GAE/g, respectively, in the stem hot water extract. ABTS and DPPH radical scavenging activities were 541.1±21.0 and 649.5±6.6 ㎍/mL, respectively, in stem hot water extract. All extracts were non-cytotoxic in HepG2 cells, but 200 ㎍/mL stem extracts tended to decrease the viability of RAW 264.7 cells. The highest xanthine oxidase inhibitory activity was 43.68% in the root hot water extract at 200 ㎍/mL. The expression level of MMP-9 was significantly decreased in the asparagus extracts. The highest GGT, AST, and LDH activities showed a concentration-dependent decrease in the stem ethanol extract. In conclusion, the presence of bioactive substances in the non-edible extracts of asparagus was confirmed for the development of extracts with antioxidant, hepatoprotective and anti-gout activities.

• Journal of the Korean Society of Radiology
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• v.15 no.1
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• pp.63-70
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• 2021

Radiographic contrast agents are used for diagnostic purposes and are one of the factors affecting measured values in bone density tests. They are absorbed into tissues and have an effect of increasing the measured values of bone density, so they are avoided as much as possible before performing a bone density test. MRI contrast agents, which have different physical properties and mechanisms of action than radiographic contrast agents, are based on gadolinium, a metal element. They have radiopacity characteristics, so MRI are generally performed prior to examination using radiation. The purpose of this study was to investigate the effects of MRI contrast agents on bone mineral density examination using dual energy X-ray absorption. Two types of gadolinium based MRI contrast agents were injected into an acrylic water tank for each volume, and the humanoid spine phantom was inserted and the BMD and T-score from (L1-L4) were analyzed by scanning a total of 30 times, 5 times for each injection type. The average value of the measured total (L1-L4) bone density for each of the two contrast agents was 0.952±0.052, 0.957±0.050, and 0.956±0.05g/㎠, respectively, for the Gadoterate Meglumine component 0mL, 7.5mL and 15mL, when the gadobutrol components were 0mL, 5mL, and 10mL, there was no statistically significant difference at all sites at 0.953±0.001, 0.954±0.001, and 0.945±0.001g/㎠, respectively(p>0.05). The average value of total T-score was -0.46±0.05, -0.4±0, -0.42±0.04 when the Gadoterate Meglumine component was 0mL, 7.5mL and 15mL, respectively. When the Gadobutrol ingredients were 0mL, 5mL and 10mL, there was no statistically significant difference in all areas, with -0.46±0.05, -0.46±0.05, and 0.5±0.00, respectively. In this experiment, the MRI contrast agent was found to have no effect on bone density tests, using the dual-energy X-ray absorption method. There is a limitation in that physical conditions such as kidney and health conditions etc. were not taken into consideration, so further clinical research is expected to be conducted in the future.

• Journal of the Korea Organic Resources Recycling Association
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• v.30 no.4
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• pp.67-83
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• 2022

Biochar is a carbon material produced through the pyrolysis of agricultural biomass with limited oxygen condition. It has been suggested to enhance the carbon sequestration and mineralization of soil carbon. Objective of this study was to investigate soil potential carbon mineralization and carbon dioxide(CO₂) emissions in different soils cooperated with barely straw and livestock manure biochars in the closed chamber. The incubation was conducted during 49 days using a closed chamber. The treatments consisted of 2 different biochars that were originated from barley straw and livestock manure, and application amounts were 0, 5, 10 and 20 ton ha^-1 with different soils as upland, protected cultivation, converted and reclaimed. The results indicated that the TC increased significantly in all soils after biochar application. Mineralization of soil carbon was well fitted for Kinetic first-order exponential rate model equation (P<0.001). Potential mineralization rate ranged from 8.7 to 15.5% and 8.2 to 16.5% in the barely straw biochar and livestock manure biochar treatments, respectively. The highest CO₂ emission was 81.94 mg kg^-1 in the upland soil, and it was more emitted CO₂ for barely straw biochar application than its livestock biochar regardless of their application rates. Soil amendment of biochar is suitable for barely straw biochar regardless of application rates for mitigation of CO₂ emission in the cropland.