• Journal of the Korean Society of Propulsion Engineers
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• v.17 no.3
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• pp.67-75
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• 2013

The numerical analysis for the verification of preburner's cooling characteristics applying to kerosene-LOx rocket engine has been fulfilled. The distribution of combustion gas properties in primary combustion zone was calculated by the mixture ratio based on head injector arrangement, the properties of oxygen flowing in wall channels as coolant were applied under real-gas conditions, and multi-phase mixing model was employed to calculate the mixing process of primary combustion zone with liquid oxygen which was used for wall cooling. The results of numerical analysis were compared with the experimental results, hence thermo-physical properties in cooling channels and a combustor could be quantitatively identified.

• Journal of Life Science
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• v.27 no.11
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• pp.1299-1307
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• 2017

The quality characteristics of three non-genetically modified (GM) LRS soybean cultivars free of LOX 1, 2 and 3, such as Jinyang, Hayoung and Daebok, were compared to the characteristics of Taekwang, a soybean with LOX 1, 2 and 3 and general contents of raffinose and stachyose. Taekwang was used as a control soybean. The weights of 100 for Taekwang and Hayoung soybeans were significantly higher than those of the other samples. The crude-protein contents of the Jinyang and Hayoung soybeans were significantly higher than the crude-protein content of the Taekwang soybeans. Similar tofu yields were observed in the Taekwang, Hayoung and Daebok soybeans. The highest tofu yield was observed in the Hayoung soybeans. The isoflavone contents of the soybeans and tofu were 1.4-1.6 times and 1.8-3.4 times higher than the contents of the control soybeans, respectively. The total phenol contents of the Hayoung and Daebok soybeans were significantly higher than the contents of the control soybeans. Additionally, the total phenol and flavonoid contents were significantly higher in the tofu made from the LRS cultivars than in the tofu made from the control cultivar. The antioxidant activities of the Taekwang soybeans were higher than the antioxidant activities of the LRS-cultivar soybeans. However, the antioxidant activities of tofu made from the LRS cultivars were significantly higher than the antioxidant activities of tofu made from the control cultivar. The results suggested that the soybeans of the LRS cultivars were suitable for tofu products. The Hayoung cultivar may be the most suitable due to its higher crude protein and isoflavone contents and its significant antioxidant activity.

• Journal of the Korean Society of Food Science and Nutrition
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• v.40 no.10
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• pp.1361-1370
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• 2011

Antioxidant and anti-inflammatory activities of eugenol and its derivatives from clove (Eugenia caryophyllata Thunb.) were evaluated using in vitro assay systems by measuring 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical, cyclooxygenase-2 (COX-2), and 15-lipoxygenase (15-LOX). Among eight different crude medicinal drugs tested, volatile extracts of clove extracted by steam distillation extraction (SDE) showed potent DPPH radical scavenging activity ($IC_{50}$=8.85 ${\mu}g/mL$) as well as strong inhibitory activity against COX-2 (58.15%) and 15-LOX (86.15%) at 10 ${\mu}g/mL$ and 25 ${\mu}g/mL$, respectively. Major volatile components of clove were identified as eugenol, trans-caryophyllene, and acetyleugenol by GC-MS analysis. Out of three eugenol derivatives, eugenol, methyl eugenol, and acetyl eugenol, eugenol showed the strongest DPPH radical scavenging activity and COX-2 inhibitory activity, whereas methyl eugenol exhibited the strongest 15-LOX inhibitory activity. Finally, the contents of the three eugenol derivatives in clove were quantified by analytical HPLC. Contents of eugenol and acetyl eugenol in clove were 6.95% and 1.85% per dry weight, respectively. These results suggest that eugenol and its derivatives in steam distilled extract of clove may be useful as potential antioxidant and anti-inflammatory agents.

• Journal of the Korean Society of Food Science and Nutrition
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• v.26 no.3
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• pp.376-382
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• 1997

Antioxidative characteristics of doenjang(fermented soybeans paste) phenolics on the lipid oxidation systems were studied by the determination of the oxidative related activity including lipoxygenase (LOX) inhibition, metal chelating and free radical scavengning of doenjang phenolics. Manlikong variety containing the highest amounts of phenolic compounds among the soybean variety, was used for doenjang processing. Doenjang was prepared by the series of processes including soaking for overnight, cooking for 1hr at 12Lb, first fermentation (3 days at 30$\pm$2$^{\circ}C$) for the preparation of meju(soybean koji) after inoculation of Asp. oryzae, and further fermentation(60 days at 30$\pm$2$^{\circ}C$) for the ripening after addition of salt 13% to meju. In order to investigate the antioxidative activity of phenolics in doenjang, the doenjang phenolics was extracted with methanol form freeze dried defatted doenjang. Antioxidative effects of methanol extract on linoleic acid oxidation system were observed by the significantly decreased levels of peroxide and conjugated diene formation. In addition, methanol extract resulted in the inhibition of LOX activity. and also, metal(FeCl$_3$) chelation and free radical scavengning activities were increased with increasing concentration of methanol extract.

• Journal of the Korean Society of Propulsion Engineers
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• v.24 no.6
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• pp.93-100
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• 2020

The turbopump of the liquid rocket engine adapts an inducer to minimize the cavitation due to the variations of the propellants supply condition. However, the inducer introduces cavitation instabilities which are well-known problems in the engine development. In this paper, operational characteristics by the cavitation instabilities are analyzed and the reliability of the engine is checked when the first stage engine of the KSLV-II is tested at the low inlet pressure conditions. The characteristic frequencies representing the cavitation instabilities of the LOx pump are clearly found in various high frequency sensor signals around the entire engine in addition to the LOx and fuel pump.

• Biomedical Science Letters
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• v.27 no.4
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• pp.277-282
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• 2021

Hydrocotyle is a genus of prostrate, perennial aquatic or semi-aquatic plants formerly classified in the family Apiaceae, now in the family Araliaceae. Lipoxygenases (LOX) are present in the human body and play an important role in the stimulation of inflammatory reactions. Ethanolic extracts of five Hydrocotyle species (H. ramiflora, H. maritima, H. nepalensis, H. sibthorpioides, and H. yabei) showed inhibition of 23.5~50.6% at 2.0 mg/mL. Their extracts showed LOX inhibition in half maximal effective concentration (EC₅₀) range 15.1~15.7 ㎍/mL. Hyaluronic acid is a glycosaminoglycan, a major component of the extracellular matrix Five extracts of these species inhibited less than 23.0% of Hyaluronidase (HAase) activity at a concentration of 2.0 mg/mL Xanthine oxidase (XO) is a form of xanthine oxidoreductase, a type of enzyme that generates reactive oxygen species. Five Hydrocotyle species were found to have inhibitory activity of XO at 2.0 mg/ml, with 65% having greater than 50% inhibition. H. ramiflora exhibited the highest activity with an inhibition of 80.0%. The results suggested that Lipoxygenases, Hyaluronidase, and Busan 47340, Republic of Korea from five Hydrocotyle species might be multifunctional and prevent the degradation of allergic reactions and inflammation.

• Journal of the Korean Society of Propulsion Engineers
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• v.24 no.1
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• pp.1-8
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• 2020

In this study, a configuration design of a CH₄/LOx small rocket engine was made and test system was established for the performance evaluation. A coaxial swirl injector was chosen because of its remarkable atomization performance and low combustion instability. Three aspect ratios for the combustion chamber configuration, i.e., 1.5, 1.8, and 2.1 were also set for the comparison of the combustion efficiency. The reliability of the thrust measurement rig was enhanced by pre-and post-calibration process. From the preliminary ground hot-firing test, the measured thrust and specific impulse values were 89.2 N and 181.8 s, respectively, which were 21.6% lower than the ideal values. In addition, the efficiency of characteristic velocity was measured as 84.2%.

• Journal of Microbiology and Biotechnology
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• v.26 no.4
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• pp.700-709
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• 2016

The mitogen-activated protein kinase HOG1 (high-osmolarity glycerol response pathway) plays a crucial role in the response of yeast to hyperosmotic shock. Trichosporonoides oedocephalis produces large amounts of polyols (e.g., erythritol and glycerol) in a culture medium. However, the effects of HOG1 gene knockout and environmental stress on the production of these polyols have not yet been studied. In this study, a To-HOG1 null mutation was constructed in T. oedocephalis using the loxP-Kan-loxP/Cre system as replacement of the targeted genes, and the resultant mutants showed much smaller colonies than the wild-type controls. Interestingly, compared with the wild-type strains, the results of shake-flask culture showed that To-HOG1 null mutation increased erythritol production by 1.44-fold while decreasing glycerol production by 71.23%. In addition, this study investigated the effects of citric acid stress on the T. oedocephalis HOG1 null mutants and the wild-type strain. When the supplementation of citric acid in the fermentation medium was controlled at 0.3% (w/v), the concentration of erythritol produced from the wild-type and To-HOG1 knockout mutant strains improved by 18.21% and 21.65%, respectively.

• Journal of the Korean Society of Propulsion Engineers
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• v.9 no.4
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• pp.48-54
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• 2005

An experimental study was carried out to investigate the effect of film cooling in the lab-scale liquid rocket engine using liquid oxygen(LOx) and Jet A-1(Jet engine fuel) as propellants. Film coolants(Jet A-1 and water) was injected through the film cooling injector. The outside wall temperature of the combustor and film cooled length were determined for chamber pressure, mixture ratio, and the different geometries(injection angle) with the percent film coolant flow rate. The loss of characteristic velocity was determined for the case of film cooling with water and Jet A-1. As chamber pressure increased, the outside wall temperature increased in the nozzle but unchanged over the 9 percent film coolant flow rate for the combustion chamber used in this study. Characteristic velocity wasn't affected with the mixture ratio over the 9 percent film coolant flow rate.

• Journal of the Korean Society of Propulsion Engineers
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• v.20 no.4
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• pp.50-58
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• 2016

Korean Space Launch Vehicle (KSLV-II) Propellant Supply System charges liquid oxygen and kerosene to each propellant tank for the stages. To charge the launch vehicle propellant tank safety, the propellant charge flow rates and scenarios should be defined. First, the Propellant Supply System was modeled with 1D flow analysis program. The control valve capacity and orifice size were calculated by performing the 1D steady state simulation. Second, the 1D transient simulation was performed by using the steady state simulation results. As propellants were being charged at the each tank, the increased tank liquid level decreases the charge flow rate. Consequently, the proposed supply system satisfies the required design charging conditions.