• 대한기계학회논문집B
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• 제27권6호
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• pp.685-692
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• 2003

A numerical simulation of flame propagation in a micro combustor was carried out. Combustor has a sub -millimeter depth cylindrical internal volume and axisymmetric one-dimensional was used to simplify the geometry. Semi-empirical heat transfer model was used to account for the heat loss to the walls during the flame propagation. A detailed chemical kinetics model of $H_2/Air$ with 10 species and 16 reaction steps was used to calculate the combustion. An operator-splitting PISO scheme that is non-iterative, time-dependent, and implicit was used to solve the system of transport equations. The computation was validated for adiabatic flame propagation and showed good agreement with existing results of adiabatic flame propagation. A full simulation including the heat loss model was carried out and results were compared with measurements made at corresponding test conditions. The heat loss that adds its significance at smaller value of combust or height obviously affected the flame propagation speed as final temperature of the burnt gas inside the combustor. Also, the distribution of gas properties such as temperature and species concentration showed wide variation inside the combustor, which affected the evaluation of total work available of the gases.

• Journal of Microbiology and Biotechnology
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• 제19권11호
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• pp.1319-1327
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• 2009

Marine red algae of genus Laurencia are becoming the most important resources to produce unique natural metabolites with wide bioactivities. However, reports related to Laurencia undulata, an edible species used as folk herb, are rarely found to date. In this research, 5-hydroxymethyl-2-furfural (5-HMF) was isolated and characterized by nuclear magnetic resonance (NMR) from Laurencia undulata as well as other marine algae. The following characteristics of 5-HMF were systematically evaluated: its antioxidant activities, such as typical free-radicals scavenging in vitro by electron spin resonance spectrometry (ESR) and intracellular reactive oxygen species (ROS) scavenging; membrane protein oxidation; oxidative enzyme myeloperoxidase (MPO) inhibition; as well as expressions of antioxidative enzymes glutathione (GSH) and superoxide dismutase (SOD) on the gene level using the polymerase chain reaction (PCR) method. The results demonstrated that 5-HMF could be developed as a novel marine natural antioxidant or potential precursor for practical applications in the food, cosmetic, and pharmaceutical fields.

• 한국잡초학회지
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• 제30권3호
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• pp.308-321
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• 2010

우리나라 농경지에서 발생하는 잡초 68과 433종에 대한 공통적인 약어(가칭 KSWS code, the Korean Society Weed Science code)를 만들어 잡초연구자의 연구효율성을 증진시키고자 한다. 이들 약어는 이미 미국잡초학회에서 널리 사용되고 있는 Bayer code를 인용하여 한국 잡초 현황에 맞게 재구성하였다. KSWS code는 알파펫 5자로 구성되며, 속명에서 3자, 종소명에서 2자를 떼어내어 조합을 만들었다. 그리고 변이종이 있을 경우에는 속명의 1자, 변이종명의 1자로 KSWS code를 조합하였다.

• 상하수도학회지
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• 제23권4호
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• pp.491-497
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• 2009

The purpose of this study is to propose a method of controlling redtide microbes which grow abundantly and form harmful algal bloom in eutrophic waterbody with yellow loess and hydrogen peroxide. In the laboratory test, hydrogen peroxide was applied to single species of C. polykrikoides and multispecies of redtide microbes. The seawater was evaluated by the pre-test analysis including chlorophyll-a, luminance and transmittance. The test results showed that both single and mixed species of redtide microbes could be controlled with the dose of 30mg $H_2O_2/L$. Residual hydrogen peroxide was completely decomposed with the addition of powdered yellow loess at 2g/L~10g/L. However, the decomposition rate of residual hydrogen peroxide for sintered granular yellow loess was relatively low compared to the use of powdered one. With the addition of dissolved oxygen concentration was increased at a rate of 0.013 mg DO/mg $H_2O_2$, which is a little lower than the one predicted theoretically. No evidence for any detrimental effects on Artemia, a type of brine shrimps, was shown up to the concentration of 100mg $H_2O_2/L$.

• Mycobiology
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• 제43권3호
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• pp.266-271
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• 2015

Several types of yeasts were isolated from wild flowers around Jangseong Lake in Jeollanam-do, Republic of Korea and identified by comparing the nucleotide sequences of the PCR amplicons for the D1/D2 variable domain of the 26S ribosomal DNA using Basic Local Alignment Search Tool (BLAST) analysis. In total, 60 strains from 18 species were isolated, and Pseudozyma spp. (27 strains), which included Pseudozyma rugulosa (7 strains) and Pseudozyma aphidis (6 strains), was dominant species. Among the 60 strains, Bullera coprosmaensis JS00600 represented a newly recorded yeast strain in Korea, and its microbiological characteristics were investigated. The yeast cell has an oval-shaped morphology measuring $1.4{\times}1.7{\mu}m$ in size. Bullera coprosmaensis JS00600 is an asporous yeast that exhibits no pseudomycelium formation. It grew well in vitamin-free medium as well as in yeast extract-malt extract broth and yeast extract-peptone-dextrose (YPD) broth, and it is halotolerant growing in 10% NaCl-containing YPD broth.

• Fisheries and Aquatic Sciences
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• 제24권6호
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• pp.228-234
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• 2021

A single specimen (39.4 mm standard length) of Brachaluteres ulvarum, belonging to the family Monacanthidae has been recorded for the first time from Supseom, Jeju-do Island of southern Korea on 6 March 2021. This species was characterized by the presence of a small second dorsal spine present, the posterior end of pelvic without encasing scales, and numerous thin dark longitudinal lines on body. It was morphologically similar to the B. taylori, but distinguished by the ratio of the caudal peduncle to the head length (B. ulvarum, 2.5 to 3.7 times; B. taylori, 3.5 to 5.2 times). In addition, the former is well distinguished from the latter through mitochondrial cytochrome c oxidase subunit I (COI) sequences by genetic distances of range from 0.088 to 0.090. The new Korean name "Kko-ma-jwi-chi- sog" is proposed for the genus Brachaluteres, and "Kko-ma-jwi-chi" for the species B. ulvarum.

• 식물병연구
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• 제27권4호
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• pp.155-163
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• 2021

Dried red peppers are frequently contaminated with mycotoxins during storage. To determine the effect of storage environments on fungal occurrence and subsequent mycotoxin accumulation in dried red peppers, we monitored red pepper powder and whole fruit samples for fungal occurrence under various temperatures and relative humidity (RH) conditions during 340 days. Fungal occurrences fluctuated in both pepper forms throughout the storage but they were higher in pepper powder than whole one, higher under low temperatures (-20℃, 0℃, or 4℃) than others (10℃, 25℃, or 30℃), and higher under RH 93% than RH 51% and 69% in both peppers. The samples exhibiting high fungal occurrences were associated mainly with dominant species such as Aspergillussydowii, Penicillium solitum, P. roqueforti, P. polonicum, or P. chrysogenum. Mycotoxigenic species, including A. flavus, A. ochraceus, A. westerdijkiae, A. tubingensis, and P. citrinum, were also detected throughout the samples. Although mycotoxins were not detected in the samples, mycotoxigenic potential of A. flavus, A. ochraceus, and A. westerdijkiae isolates were confirmed. These results show that low temperatures (-20℃, 0℃, or 4℃) and/or high surrounding RH (>93%) are not safe environments for storage of dried red peppers as fungal growth can occur under these conditions.

• Proceedings of the National Institute of Ecology of the Republic of Korea
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• 제3권3호
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• pp.172-177
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• 2022

Two unrecorded fungi, Diaporthe perseae and Fusarium falciforme, were isolated from soil sampled from Dokdo in Korea. There have been many reports of Diaporthe sp. and Fusarium sp. in mainland Korea but none of them have reported in Dokdo so far. We used the morphological features and two molecular markers including the internal transcribed spacer and translation elongation factor 1-α region to compare and analyze these species with the closely related taxa. As a result, we confirmed that these fungi were unrecorded soil fungi in Korea. Then, the cultural and morphological characteristics such as the conidia of these two fungal species could be clarified. These results are expected to help us to understand the distribution of fungi in Dokdo and manage the Dokdo Island Natural Reserve.

• Membrane and Water Treatment
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• 제14권2호
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• pp.77-83
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• 2023

As a result of algal bloom, algal organic matters (AOMs) are rapidly increased in surface water. AOMs can act as precursors for the formation of harmful disinfection by-products (DBPs), which are serious problems in water treatment and human health. The main aim of this study is to characterize the formation of DBPs from AOMs produced by three different algae such as Oscillatoria sp., Anabaena sp., and Microcystis aeruginosa under different algal growth phases. In an effort to examine formation of DBPs during chlorination, chloroform (TCM), dichloroacetic acid (DCAA) and trichloroacetic acid (TCAA) were determined under various CT (product of disinfectant concentration and contact time, mg·min/L) values. Generally, the amounts of DBPs tended to increase with increasing CT values at the most growth phases. However, there was a significant difference between the amounts of DBPs produced by the three algal species at different growth phases. This result is likely due to the chemical composition variability of AOM from different algae at different growth phases. In addition, the effect of pre-ozonation on coagulation for the removal of AOMs from three algal species was investigated. The pre-ozonation had a positive effect on the coagulation/flocculation of AOMs.

• 생명과학회지
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• 제33권4호
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• pp.325-333
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• 2023

본 연구에서는 김치와 묵은지의 미생물 군집 구조와 이화학적 특성을 비교 분석하였다. 김치와 묵은지의 이화학적 특성 분석 결과 묵은지 시료들의 pH가 김치보다 더 낮았으며, 산도는 더 높은 것으로 나타났다. 김치와 묵은지 간의 염도에는 차이가 없는 것으로 나타났으며, 김치에서 당도가 묵은지보다 높은 것으로 나타났다. α-diversity 분석 결과 김치와 묵은지 사이에 종 추정치와 종 풍부도 지수는 차이가 없는 것으로 나타났으나, 계통발생학적 차이를 반영한 phylogenetic diversity 지수는 묵은지에서 김치보다 유의한 수준으로 높은 것으로 나타났다. 김치와 묵은지의 미생물 군집을 생물학적 분류수준에 따라 분석한 결과 두 그룹 모두 공통적으로 과(family) 수준에서 Lactobacillaceae가 가장 우점하였으나, 높은 내산성을 갖거나 김치 내에서 높은 성장 경쟁력을 갖는 것으로 알려진 Pediococcus 속과 Lactobacillus 속 유산균의 상대적인 분포가 묵은지에서 높은 것으로 나타났다. 김치와 묵은지의 전체 미생물 군집 구조에 통계학적으로 차이가 있는지 분석하기 위해 beta set-significance 분석을 수행한 결과 김치와 묵은지 두 그룹의 전체 미생물 군집구조가 통계학적으로 신뢰수준에서 매우 다른 것으로 나타났으며, 김치에서 상대적으로 높은 Weissella kandleri의 분포와 묵은지에서 상대적으로 높은 Pediococcus inopinatus의 높은 분포가 김치와 묵은지의 전체 미생물 군집 구조 차이에 가장 큰 영향을 미치는 것으로 나타났다.