• 한국응용곤충학회지
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• 제28권3호
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• pp.120-145
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• 1989

1985년부터 3개년에 걸쳐서 전국 387개 시.읍.면의 1, 160개 논에서 벼기생선충을 조사한 결과 우리나라 논에서 벼와 관련된 선충은 35종이 밝혀졌으며 본 조사로 26종이 새로이 추가되었고 세계적으로는 Criconemoides informis, Criconemella paragoodeyi, Criconema (Criconema) jaejuense, Ditylenchus longicauda, Eutylenchus africanus, Merlinius n. sp., Meiodorus n. sp., Ogma (Homogma) serrata, Ogma (Homogma) insulicum, Orientylus orientalis, Paratylenehus lepidus, Pararotylenchus Pini, Triνersus n. sp., Tylenchorhynchus claνicaudatus, Tylench-orhynchus nudus등 15종이 벼기생선충으로 새로이 기록되었다. 우리 나라에서 처음으로 발견된 Criconemella paragoodeyi, Ditylenchus longicauda 및 Merlinius n. sp. 등은 전국적으로 분포 하고 있을 뿐 아니라 밀도 또한 높으므로 벼의 중요한 기생선충으로 사료된다. 벼뿌리선충은 전국적으로 분포하며 밀도 또한 높았고, 애벼뿌리선충은 남부지방에서는 벼뿌리선충과 같이 분포되고 있으나 북부지방으로 갈수록 점차 밀도가 낮아지는 경향을 나타냈다

• 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.

• 생태와환경
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• 제42권2호
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• pp.212-220
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• 2009

본 연구는 2008년 11월에 마산저수지를 대상으로 어류 종조성 및 섭식길드 및 오염내성길드에 따른 생태지표 특성을 분석하고, 이와 연관된 화학적 수질 특성 변화를 분석하였다. 채집된 어류는 총 12종(6과)으로 나타났고, 주요 우점종은 피라미, 치리, 참붕어 등으로 나타났다. 한국 고유종은 3종만이 출현하였으며, 외래도입종은 떡붕어 1종이 출현하였다. 생태지표 특성 분석에 따르면, 내성종 및 잡식종의 상대풍부도는 각각 98%로 단연 우점하는 것으로 나타나, 이화학적 질적저하 및 물리적 서식지 교란요인에 의한 영향을 반영하고 있었다. 호안에 따른 종분포 특성 분석 결과, 정수식물이 발달한 호안에서 대부분의 어류가 95% 이상이 채집된 것으로 나타났다. 또한 하상 기질 특성에 따른 분석 결과, 뻘(Silt)로 된 구간에서 가장 많은 종 (11종, 91.7%)이 채집되어, 하상기질에 따라 유의한 차이를 보이고 있었다. 화학적 수질자료 분석에 따르면, 호수 영양상태 지표인 총인(TP) 및 Chl-a의 농도는 모두 과영양상태인 것으로 나타났으며, 호수의 유기물오염의 지표로 사용되는 COD도 평균 10.9 mg $L^{-1}$로 나타났다. 마산저수지의 이러한 수질저하는 어류의 섭식구조(잡식종의 증가) 및 내성종의 증가 등을 통해 반영되었다. 향후 마산저수지의 어류상 및 어류 종조성이 향상을 위해서 수질 개선 및 서식지 복원이 펼요할 것으로 사료된다.

• 한국균학회소식:학술대회논문집
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• 한국균학회 2018년도 춘계학술대회 및 임시총회
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• pp.13-13
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• 2018

Alternaria is a ubiquitous fungal genus, widely distributed in the environment and a range of different habitats. It includes both plant pathogenic and saprophytic species, which can affect crops in the field or cause post-harvest spoilage of plant fruits and kernels. Numerous Alternaria species cause damage to agricultural products including cereal grains, fruits and vegetables, and are responsible for severe economic losses worldwide. Most Alternaria species have the ability to produce a variety of secondary metabolites, which may play important roles in plant pathology as well as food quality and safety. Alternariol (AOH), alternariol monomethyl ether (AME), tenuazonic acid (TeA), tentoxin (TEN) and altenuene (ALT) are considered the main Alternaria compounds thought to pose a risk to human health. However, food-borne Alternaria species are able to produce many additional metabolites, whose toxicity has been tested incompletely or not tested at all. Both alternariols are mutagenic and their presence in cereal grain has been associated with high levels of human esophageal cancer in China. TeA exerts cytotoxic and phytotoxic properties, and is acutely toxic in different animal species, causing hemorrhages in several organs. The possible involvement of TA in the etiology of onyalai, a human hematological disorder occurring in Africa, has been suggested. Altertoxins (ALXs) have been found to be more potent mutagens and acutely toxic to mice than AOH and AME. Other metabolites, such as TEN, are reported to be phytotoxins, and their toxicity on animals has not been demonstrated up to now. Vegetable foods infected by Alternaria rot are obviously not suitable for consumption. Thus, whole fresh fruits are not believed to contribute significantly with Alternaria toxins to human exposure. However, processed vegetable products may introduce considerable amounts of these toxins to the human diet if decayed or moldy fruit is not removed before processing. The taxonomy of the genus is not well defined yet, which makes it difficult to establish an accurate relationship between the contaminant species and their associated mycotoxins. Great efforts have been made to organize taxa into subgeneric taxonomic levels, especially for the small-spored, food associated species, which are closely related and constitute the most relevant food pathogens from this genus. Several crops of agricultural value are susceptible to infection by different Alternaria species and can contribute to the entry of Alternaria mycotoxins in the food chain. The distribution of Alternaria species was studied in different commodities grown in Argentina. These food populations were characterized through a polyphasic approach, with special interest in their secondary metabolite profiles, to understand their full chemical potential. Alternaria species associated with tomato, bell pepper, blueberry, apples and wheat cultivated in Argentina showed a surprisingly high metabolomic and mycotoxigenic potential. The natural occurrence of Alternaria toxins in these foods was also investigated. The results here presented will provide background for discussion on regulations for Alternaria toxins in foods.

• 한국약용작물학회지
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• 제22권4호
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• pp.301-305
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• 2014

This study was carried out to investigate the vegetation and habitat environment of Sageretia thea which is distributed in Jeju island, Korea. Sageretia thea were mainly distributed to the west area in Jeju island. Soil pH and EC of Sageretia thea habitat were 5.8 and $0.34dS{\cdot}m^{-1}$. The contents of organic matter, available phosphate, exchangeable potassium, exchangeable sodium, exchangeable magnesium and exchangeable calcium were 15.27%, $13.6mgkg^{-1}$, $0.27cmol_+kg^{-1}$, $1.3cmol_+kg^{-1}$, $1.7cmol_+kg^{-1}$, $4.9cmol_+kg^{-1}$, respectively. Thirty one taxa including 25 families, 31 genus, 27 species and 4 varieties were identified surrounding Sageretia thea habitat. Specific plant species were 1 taxon in III grade, 1 taxon in I grade and 3 taxa in I grade.

• 한국수산과학회지
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• 제37권4호
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• pp.295-306
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• 2004

Spatial patterns in the macrobenthic community structure in the inter- and subtidal zones in front of the Iwon Dike and environmental variables were examined in August 2001, In total, 156 macrobenthic species(123 intertidal species and 90 subtidal species) were recorded during this study, predominately polychaetes $(40{\%})$, bivalves $(22{\%})$, and crustaceans $(22{\%})$. Polychaetes made up less than $40{\%}$ of the intertidal communitr, but more than $50{\%}$ of the subtidal community. The mean density during this study was $1,456ind./m^{2}.$ Multivariate analysis (multidimensional scaling) revealed significant differences in community structure among four regions: near the Iwon dike (B1), the high and middle intertidal zone (B2), low intertidal zone (Al), and subtidal zone (A2). The number of species, total density, and diversity (H') varied significantly among the four regions. The distribution of macrobenthic community was affected by environmental variables, such as ${\%}$ silt/clay content, total sulfide, lose of ignition, and chemical oxygen demand. These environmental variables were negatively correlated with the dominant species (Nephtys polybranchia, Umbonium thomasi, and Scoloplos armiger) in the intertidal area, but positively correlated with the dominant species (Lumbrineris cruzensis, Notomastus latericeus, and Moerella sp.) in the subtidal area. Environmental variables $({\%}\;silt/clay content and total sulfide)$ were positively correlated with the dominant species (Heteromastus filiformis) in region Bl, but negatively correlated with the dominant species (Umbonium thomasi and Scoloplos koreanus) in region B2. Amphipods Urothoe spp. and Monoculodes koreanus were the dominant species in region Al. Umbonium thomasi, the dominant species in region B2, was not found in regions Bl or Al. We suggest that the inter-specific competition for territory and exposure to seawater may be important factors controlling the macrobenthic community structure in the inter- and subtidal zones in front of the Iwon Dike.

• 한국환경과학회지
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• 제1권1호
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• pp.77-88
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• 1992

Distribution patterns of the chemical species, contained or dissolved in the sediments and porewater, were studied from the submarine environments around Deok-Jeok Island, Yellow Sea. The sediments in the study area are predominantly composed of medium to coarse sands, and consequently of very low organic carbon (0.003%) -0.26%o dry weight sediments). As opposed to the strong enrichment of porewater with nutrients and heavy metals in the ordinarily muddy, organic-rich sediillents, the porewater enrichment is not intense in this sandy, organic-poor sediments: porewater phosphate is enriched to the maximum of only seven (average two) times over that in the bottom water. Concentrations of the heavy metals dissolved in porewater show a bit greater enrichment than the nutrient: Zn shows the lowest enrichment (7 times that of the bottom water) and Mn the highest (450 times that of the bottom water). However, these enrichments of the chemical species in porewater are the natural consequences of decomposition of the organic matter in sediments, and still fall short in the magnitude of those in the muddy, organic-rich sediments. Mining of the sands in the study area may pose a threat to the seawater quality as it causes a large scale porewater discharge to the bottom water. The additional supply of the nutrients by this discharge may develop an eutrophic state and, in consequence, an excessive nitrification of the water column. Since the residence times of the nutrients are much longer than those of the heavy metals, a long-term monitoring of the concentration changes in the porewater nutrients is very important to assess the potential deterioration of the seawater associated with the sand mining in the study area.

• 한국지하수토양환경학회지:지하수토양환경
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• 제22권5호
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• pp.30-39
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• 2017

In this study, the predictive toxicity of barley Hordeum vulgare was estimated using a modified terrestrial biotic ligand model (TBLM) to account for the toxic effects of $CuOH^+$ and $CuCO_3(aq)$ generated at pH 7 or higher, and this was compared to that from the original TBLM. At pH values higher than 7, the difference in $EA_{50}\{Cu^{2+}\}$ (half maximal effective activity of $Cu^{2+}$) between the two models increased with increasing pH. As Mg concentration increased from 8.24 to 148 mg/L in the pH range of 5.5 to 8.5, the difference in $EA_{50}\{Cu^{2+}\}$ increased, and it reached its maximum at pH 8. The difference in $EC_{50}[Cu]_T$ (half maximal effective concentration of Cu) between the two models increased as dissolved organic carbon (DOC) concentration increased when pH was above 7. Thus, for soils with alkaline pH, the toxic effect of $CuOH^+$ and $CuCO_3(aq)$ are greater at higher salt and DOC concentrations. The acceptable Cu concentration in soil porewater can be estimated by the modified TBLM through deterministic method at pH levels higher than 7, while combination of TBLM and species sensitivity distribution through the probabilistic method could be utilized at pH levels lower than 7.

• Bulletin of the Korean Chemical Society
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• 제6권3호
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• pp.145-148
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• 1985

The effect of anionic polyelectrolytes, poly(styrenesulfonate) (PSS) and poly(vinylsulfonate) (PVS), on the charge transfer complexing between indole derivatives and methyl viologen($MV^{++}$) cation was investigated. The results were compared with effect of NaCl and an anionic surfactant, sodium dodecylsulfate (SDS). Both PSS and PVS enhanced the complex formation of neutral species (indole and indole acetate at low pH), zwitter ionic tryptophan, and positively charged tryptamine and tryptophan at low pH with $MV^{++}$. This result was attributed to the contribution of hydrophobic interaction, in addition to electrostatic interaction. The enhancing effect of PSS was much higher than that of PVS reflecting the higher hydrophobicity of PSS. The interaction between indole acetate anion and $MV^{++}$ was greatly reduced by addition of PVS and PSS. The higher charge density of PVS was appeared as greater reducing effect indicating the importance of electrostatic force in this case. In all cases, the effect of polyelectrolytes showed maxima, and further addition of PVS and PSS decreased the effect. This behavior was explained in terms of distribution of indole derivatives and $MV^{++}$ in domain of polyanions. The complex formation constants and molar absorptivities of complexes were determined, and the values were compared with those in water and SDS solutions.

• Bulletin of the Korean Chemical Society
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• 제35권1호
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• pp.236-242
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• 2014

Isospecific propylene polymerization behavior of meta- and para-Lewis base (E) functionalized unbridged zirconocenes ($[1-(E_n-Ph)-3,4-Me_2C_5H_2]_2ZrCl_2$, E = $NMe_2$, OMe; n = 1 or 2) was investigated under bulk conditions. Catalytic activity of the zirconocenes, and molecular weight and isotacticity of polypropylenes are found to be dependent on the position and number of the Lewis base functional groups in the zirconocenes. All the crude polypropylenes possess a broad molecular weight distribution and multi-melting transitions, indicating an involvement of multi-catalytic active species in the polymerization. The highest [mmmm] value of an isotactic portion of the polypropylenes reached 89%, which is higher than that (85%) from the well-known $C_2$-symmetric EBIZr (rac-$Et(Ind)_2ZrCl_2$) catalyst. These results support that the in situ generated, rigid rac-like cation-anion pair through the Lewis acid-base interactions between the functional groups of zirconocenes and methylaluminoxane anion is effective in the formation of isotactic polypropylene under bulk propylene polymerization conditions.