• The Journal of the Petrological Society of Korea
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• v.28 no.3
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• pp.157-169
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• 2019

Pseudotachylytes, produced by frictional heating during seismic slip, provide information that is critical to understanding the physics of earthquakes. We report the results of occurrence, structural characteristics, scanning electron microscopic observation and geochemical analysis of pseudotachylytes, which is presumed to have formed after the Late Cretaceous in outcrops of the Paleoproterozoic granitic gneiss on the Bulil waterfall of the Jirisan area, Yeongnam massif, Korea. Fault rocks, which are the products of brittle deformation under the same shear stress regime in the study area, are classified as pseudotachylyte and foliated cataclasite. The occurrences of pseudotachylyte identified on the basis of thickness and morphology are fault vein-type and injection vein-type pseudotachylyte. A number of fault vein-type pseudotachylytes occur as thin (as thick as 2 cm) layers generated on the fault plane, and are cutting general foliation and sheared foliation developed in granitic gneiss. Smaller injection vein-type pseudotachylytes are found along the fault vein-type pseudotachylytes, and appear in a variety of shapes based on field occurrence and vein geometry. At a first glance fault vein-type seudotachylyte looks like a mafic vein, but it has a chemical composition almost identical to the wall rock of granitic gneiss. Also, it has many subrounded clasts which consist predominantly of quartz, feldspar, biotite and secondary minerals including clay minerals, calcite and glassy materials. Embayed clasts, phenocryst with reaction rim, oxide droplets, amygdules, and flow structures are also observed. All of these evidences indicate the pseudotachylyte formed due to frictional melting of the wall rock minerals during fault slip related to strong seismic faulting events in the shallow depth of low temperature-low pressure. Further studies will be conducted to determine the age and mechanical aspect of the pseudotachylyte formation.

• Journal of Life Science
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• v.29 no.1
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• pp.76-83
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• 2019

In this study, the optimal growth and poly(3-hydroxybutyrate) (PHB) biosynthesis of Pseudomonas sp. EML2 were established using waste frying oil (WFO) as a cheap carbon source. The fatty acid composition of WFO and fresh frying oil (FFO) were analyzed by gas chromatography. The unsaturated and saturated fatty acid contents of the FFO were 82.6% and 14.9%, respectively. These contents changed in the WFO. The compositional change in the unsaturated fatty acid content in the WFO was due to a change in its chemical and physical properties resulting from heating, an oxidation reaction, and hydrolysis. The maximum dry cell weight (DCW) and PHB yield (g/l) of the isolated strain Pseudomonas sp. EML2 were confirmed under the following culture conditions: 30 g/l of WFO, 0.5 gl of $NH_4Cl$, pH 7, and $20^{\circ}C$. Based on this, the growth and PHB yield of Pseudomonas sp. EML2 were confirmed by 3 l jar fermentation. After the cells were cultured in 30 g/l of WFO for 96 h, the DCW, PHB content, and PHB yield of Pseudomonas sp. EML2 were 3.6 g/l, 73 wt%, and 2.6 g/l, respectively. Similar results were obtained using 30 g/l of FFO as a carbon source control. Using the FFO, the DCW, PHB content, and PHB yield were 3.4 g/l, 70 wt%, and 2.4 g/l, respectively. Pseudomonas sp. EML2 and WFO may be a new candidate and substrate, respectively, for industrial production of PHB.

• Journal of the Korean Society of Urban Environment
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• v.18 no.4
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• pp.473-483
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• 2018

In this study, we have developed a lab scale bioreactor to identify the characteristics of nitrification reaction according to operation condition (temperature, inhibitor (as Cl), activated nitrifying bacteria (ANB). etc) to improve nitrification efficiency at low temperature. Recovery rate of nitrification took about 4 days to reach the normal level by injected ANB after inhibition shock of CI injection at $20^{\circ}C$, when measured the concentration of $NO_2{^-}-N+NO_3{^-}-N$ in the effluent. In the case of $10^{\circ}C$, recovery of nitrification rate took about 4 days to reach the level of half to the normal level and 7 days for complete recovery which took 3 days more than those at $20^{\circ}C$. At $10^{\circ}C$ considering the winter season, the specific nitrification rate(SNR) of the from 1 day to 6 days after injected ANB according to its operation condition increased from 0.029 to 0.767 mgN/gSS/hr. The simulated SNR for the 8th day after the injected ANB at $10^{\circ}C$ was 0.840, 3.625 mgN/gSS/hr, respectively as linear function and exponential function, expecting to exceed level of 2.592 mgN/gSS/hr at normal condition. It was confirmed that injection of ANB during low temperature operation has many effects for improving nitrification efficiency through this study. In future studies, if further studies are carried out the determination of ANB injection and the design of efficient ANB reactor considering the changes of operating characteristics by site, it will contribute to the improvement of nitrification efficiency in winter season.

• Journal of Mushroom
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• v.19 no.2
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• pp.88-95
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• 2021

This study was carried out to breed new variety of Pleurotus nebrodensis. We have collected and tested characteristics of genetic resources from domestic and abroad since 2015. The varieties of P. nebrodensis from China are grown by farmers, but those have been unstable fruiting and are weak against bacterial diseases. To solve this problem, we bred the unique domestic variety 'Uram' of P. nebrodensis and the results of the characteristic test for the new 'Uram' are as follows. The proper temperature for the mycelial growth was 26~29℃ and fruit body growth temperature was 15~18℃. It was similar to the control variety KME65035 of P. nebrodensis in the pileus form of a flat and white color. The number of days required for initial fruting was 5 days for bottle cultivation and 6 days for bag cultivation which was 2-4 days shorter than that of the control variety. The pileus diameter was 32.6-37.0 mm which was smaller but the fruit body length was 130.4 mm, which was longer than those of the control variety. The effective number of fruit bodies was 1.8 in bottle cultivation and 2.9 in bag cultivation, which was more than those of the control variety. The yield rate was 93.3-100%, which was more stable than those of the control variety. In bottle cultivation and bag cultivation, the yield was 173.1 g/bottle (1100 cc) and 283.4 g/bag (1.2 kg), respectively, which was 25-44% higher than those of the control variety 138.0 g/bottle (1100 cc) and 197.4 g bag (1.2 kg). When incubating the parent and control varieties of 'Uram', the replacement line was clear and as a result of mycelial DNA RAPD-PCR reaction, the band pattern was different from that of the parent and control varieties, confirming the hybrid species.

• Korean Journal of Agricultural and Forest Meteorology
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• v.23 no.4
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• pp.366-373
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• 2021

This study attempted to establish a field data-based write analysis standard by analyzing field observation data, which is non-linear data of southern garlic. Five regions, including Goheung, Namhae, Sinan, Changnyeong, and Haenam, were selected for analysis. Observation values for each observation station were extracted from the temperature data of farmland in the region through inverse distance weighted. Southern-type garlic production and temperature data were collected for 10 years, from 2010 to 2019. Local regression analysis (Kernel) of the obtained data was performed, and growth temperatures were analyzed, such as 0.8 (18.781℃), 0.9 (18.930℃), 1.0 (19.542℃), 1.1 (20.165℃), and 1.2 (21.042℃) depending on the bandwidth. The analyzed optimum temperature and the grown temperature (4℃/25℃) were applied to extract the growth temperature for each temperature by using the temperature response model analysis. Regression analysis and correlation analysis were performed between the analyzed growth temperature and production data. The coefficient of determination(R²) was analyzed as 0.325 to 0.438, and in the correlation analysis, the correlation coefficient of 0.57 to 0.66 was analyzed at the significance probability 0.001 level. Overall, as the bandwidth increased, the coefficient of determination was higher. However, in all analyses except bandwidth 1.0, it was analyzed that all variables were not used due to bias. The purpose of this study is to accommodate all data through non-linear data. It was analyzed that bandwidth 1.0 with a high coefficient of determination while accepting modeling as a whole is the most suitable.

• Korean Journal of Poultry Science
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• v.49 no.4
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• pp.255-264
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• 2022

This study was performed to investigate the effects of dietary supplementation with ginseng by-products on growth, organ development, blood biochemical profiles, immune response, and stress parameter of broilers reared in high ambient temperatures. One hundred one-day-old male chicks (Ross 308) were used. At week two, the birds were randomly allocated into five dietary groups; control (CON), 0.5% ginseng berry (GB1), 1.0% ginseng berry (GB2), 0.5% ginseng leaves and stems (GLS1), and 1.0% ginseng leaves and stems (GLS2). The temperature was maintained at 32±1℃from 9 AM to 5 PM. Growth, serum immunoglobulins and corticosterone levels were monitored and analyzed. No significant differences among groups were observed in growth. However, during the finisher period (21~35d) and overall period (7~35 d), body weight gain in all supplemented groups tended higher than CON group. Blood biochemical profiles did not significantly differ among treatment groups except in bilirubin level. Serum immunoglobulins and corticosterone level showed no significant differences among groups. IgM and IgG levels were numerically higher in GLS1 than in other groups, but the difference was not significant. Corticosterone level also tended lower in all supplemented groups than in CON group, and larger decreases were observed in groups with higher ginseng by-product concentration. In conclusion, dietary supplementation of ginseng by-products shows potential to reduce heat stress in growing broilers with no negative effect on productivity.

• Journal of Mushroom
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• v.20 no.3
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• pp.113-118
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• 2022

This study was conducted to diversify the cultivation of mushroom items and develop a competitive variety of Hypsizigus marmoreus. We focused on developing Hypsizigus marmoreus with lower bitterness, likable shape, and high yield. We have collected and tested characteristics of genetic resources from domestic and abroad since 2019. Breeding (2019), characterization (2020), productivity test (2021), and farm demonstration test (2021) have been sequentially conducted. We bred the new variety 'Yunseul' with unique traits. The optimal temperature for mycelial and fruit body growth were 22-25℃ and 15-18℃, respectively. It was similar to the control variety (Mangadak-2Ho) in the pileus form (hemispherical shape) and the cultivation period. However, it was thinner and longer than the control variety with the pileus diameter, thickness, stipe diameter, and length being 19.9 mm, 7.0 mm, 9.4 mm, and 86.3 mm, respectively. The effective number of fruit bodies was 47.8 in bottle cultivation, which was more than that of the control variety. The yield was 197.4 g/bottle (1,100 cc), which was 30% higher than the yield of the control variety, 151.9 g/bottle (1,100 cc). The parent and control varieties were also incubated alongside the new variety. The somatic incompatibility line was distinct. The band pattern in the mycelial DNA PCR reaction was different from that of the parent and control varieties, confirming the hybrid species.

• Journal of the Korean Institute of Gas
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• v.27 no.3
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• pp.52-58
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• 2023

With the increasing awareness of the importance of carbon neutrality in response to global climate change, the utilization of hydrogen as a carbon-free fuel source is also growing. Hydrogen is commonly used in fuel cells (FC), but it can also be utilized in internal combustion engines (ICE) that are based on combustion. Particularly, ICEs that already have established infrastructure for production and supply can greatly contribute to the expansion of hydrogen energy utilization when it becomes difficult to rely solely on fuel cells or expand their infrastructure. However, a disadvantage of utilizing hydrogen through combustion is the potential generation of nitrogen oxides (NOx), which are harmful emissions formed when nitrogen in the air reacts with oxygen at high temperatures. In particular, for the EURO-7 exhaust regulation, which includes cold start operation, efforts to reduce exhaust emissions during the warm-up process are required. Therefore, in this study, the characteristics of nitrogen oxides and fuel consumption were investigated during the warm-up process of cooling water from room temperature to 88℃ using a 2-liter direct injection spark ignition (SI) engine fueled with hydrogen. One advantage of hydrogen, compared to conventional fuels like gasoline, natural gas, and liquefied petroleum gas (LPG), is its wide flammable range, which allows for sparser control of the excessive air ratio. In this study, the excessive air ratio was varied as 1.6/1.8/2.0 during the warm-up process, and the results were analyzed. The experimental results show that as the excessive air ratio becomes sparser during warm-up, the emission of nitrogen oxides per unit time decreases, and the thermal efficiency relatively increases. However, as the time required to reach the final temperature becomes longer, the cumulative emissions and fuel consumption may worsen.

• Food Science and Preservation
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• v.30 no.5
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• pp.857-867
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• 2023

In this study, the extraction yield, acidic polysaccharides and ginsenosides of red and black ginseng were optimized by using the response surface methodology in consideration of the ethanol concentration and temperature of the extraction. The R² of the model formula for the yield, acidic polysaccharides and ginsenosides was 0.8378-0.9679 (p<0.1). An optimal extraction yield of 5.29% was reached for red ginseng soluble solids when 1.52% ethanol concentration was used at a temperature of 67.27℃. Additionally, the optimal extraction yield for black ginseng soluble solid was 6.11% when 3.12% ethanol concentration was used at a temperature of 66.13℃. Furthermore, the optimal conditions for extracting acidic polysaccharides from red ginseng were using an ethanol concentration of 4.03% at a temperature of 69.61℃; a yield of 1.86 mg/mL was obtained. The optimal extraction yield for acidic polysaccharides from black ginseng was 1.80 mg/mL when extracted using a concentration of 24.67% of ethanol at a temperature of 71.14℃. An optimal extraction yield of 0.22 mg/mL was reached for ginsenoside Rg₁ from red ginseng when 79.92% ethanol concentration was used at a temperature of 70.62℃. The optimal extraction yield of ginsenoside Rg₃ from black ginseng was 0.31 mg/mL when ethanol was used at a concentration of 75.70% at a temperature of 65.49℃. The ideal extraction conditions for obtaining the maximum yield of both acidic polysaccharide and ginsenoside from red and black ginseng were using ethanol at a concentration between 35 and 50% at an extraction temperature of 70℃.

• Food Science and Preservation
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• v.30 no.6
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• pp.1056-1071
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• 2023

This study aimed to investigate the quality and microbial population changes for 90 days under two fermentation conditions, outdoors and indoors (35℃), with starters (single or mixed) in soybean paste. Bacillus velezensis NY12-2 (S1), Debaryomyces hansenii D5-P5 (S2), Enterococcus faecium N78-11 (S3), and their mixtures (M) were used for the makjang fermentation. The content of amino-type nitrogen among the makjang samples was highly shown in the indoors, followed by M, S3, and S2. The glutamic and aspartic acid contents in the M sample fermented in the indoors showed the highest values of 867.42±77.27 and 243.20±15.79 mg/g, respectively. By the electronic tongue analysis, the M sample fermented in the indoors exhibited lower saltiness and higher umami than the others. Consequently, we expect that using mixed strains, such as Bacillus, Debaryomyces, and Enterococcus, under constant conditions showed potential to the quality improvement of soy products.