• Proceedings of the Korea Water Resources Association Conference
• /
• 2009.05a
• /
• pp.718-722
• /
• 2009

하도 상황이 수역(水域)에서 식생역(植生域)으로 변화하여 최종적으로 육역화(陸域化)단계로의 천이가 진행되는 현상을 하도 육역화라고 한다. 하도 육역화는 하천의 생태환경적 측면에서 많은 문제들을 야기할 수 있으며, 단일 단면 하도의 복단면 고착화로 하천 통수 단면이 감소하여 하도의 홍수 관리 기능에 심각한 위해 요소로 작용할 수 있다. 본 연구는 하도 육역화 방지를 위한 수공구조물로서 말뚝을 설치하고 그 효과를 3차원 수치모형인 FLOW-3D를 이용하여 검토하였다. 수치 모의는 구조물 주변의 복잡한 흐름 모의를 위하여 복잡한 지형지물이 있는 경우에 많이 활용되는 LES(Large Eddy Simulation) 난류 모델을 적용하였으며 세굴 및 퇴적 영향을 알아보기 위하여 유사 세굴(Sediment Scour) 모델을 적용하였다. 하도 육역화 방지 수공구조물의 효과 검토를 위하여 모형 수로의 제방 근처에 말뚝을 설치하고 말뚝직경, 설치 간격 및 배열 등을 변화시켜 구조물 주변의 동수역학적 거동, 흐름분리 효과 및 세굴영향을 수치모의를 통하여 분석하였다. 분석 결과 말뚝에 의한 흐름 분리와 국부 세굴에 의하여 하상 퇴적이 상대적으로 감소되는 효과를 나타냈으며 설치간격이 수변으로부터 말뚝 두께의 2배 그리고 흐름방향으로 말뚝 두께의 2배 이내의 간격으로 설치하여야 더욱 효과적인 것으로 나타났다. 추후 다양한 수리모형 실험을 통한 검증과 다양한 조건에 대한 수치 모의를 통하여 하도 육역화 방지 기술을 개발할 수 있을 것으로 사료된다.

• Korean Journal of Microbiology
• /
• v.54 no.3
• /
• pp.280-282
• /
• 2018

Pseudoalteromonas sp. meg-B1 belonging to Gammaproteobacteria was isolated from marine sediment in Jeju island. Here, we report the draft genome sequence of strain meg-B1 with a size of approximately 4.15 Mbp and a mean G + C content of 41.2%. The draft genome included 3,606 coding sequences, and 9 ribosomal RNA and 94 transfer RNA genes. In the draft genome, genes (e.g. choline dehydrogenase) involved in the accumulation of compatible solutes required for survival in marine environments have been identified.

• Korean Journal of Microbiology
• /
• v.34 no.3
• /
• pp.132-136
• /
• 1998

Molecular analyses of natural microbial communities are often dependent upon the obtainments of pure nucleic acids. The four methods (elution after agarose gel electrophoresis, G-75 microspin columns, hydroxyapatite mi-crospin columns, and polyvinylpolypyrrolidone (PVPP) microspin columns) were compared for the removal of PCR-inhibitory humic substances from the crude DNA extracts of marine sediment samples. The PVPP microspin columns have shown superior removal of humic substances from the crude DNA extract of marine sediment samples, with yield of $4.8{\mu}g/g$ (dry weight of sediment). The purified DNA by this rapid method was pure enough to amplify 1.5 kb fragment corresponding almost full length of 16S rRNA genes.

• Geophysics and Geophysical Exploration
• /
• v.17 no.2
• /
• pp.74-87
• /
• 2014

Analysis of multi-channel seismic reflection profiles collected from the Ulleung Basin reveals that the Quaternary sequence consists of four stratigraphic units separated by erosional unconformities. Individual stratigraphic unit includes eighteen mass transport deposits which are variable in geometric characteristics and spatial distribution. Each mass transport deposit on the seismic profile is acoustically characterized by chaotic or transparent seismic facies, and shows wedge or lens-shaped external geometry. The mass transport deposits, which comprise a succession of stacked wedges, mainly occur on the southern slope, and their thickness gradually decreases toward the basin plain. The time structure map of erosional unconformities shows that a tectonic-induced structural high and troughs toward the northwest and northeast are developed at the central part of the basin. Based on the isochron map, the mass transport deposits, originated from southern part of the study area, transported to the basin plain and can be divided into two groups by the structural high. Consequently, the mass transport deposits within the Quaternary sequence in the Ulleung Basin are largely controlled by the large amounts of sediment supply, dissociation of gas hydrate during the lowstands, and central structural high.

• Korean Journal of Microbiology
• /
• v.50 no.2
• /
• pp.119-127
• /
• 2014

The affiliations and physiological characteristics of culturable bacteria isolated from the sediments of Ross Sea, Antarctica were investigated. Sixty-three isolates obtained by cultivation were grouped into 21 phylotypes affiliated with the phyla Actinobacteria and Bacteroidetes and with the classes Alphaproteobacteria and Gammaproteobacteria by phylogenetic analysis of 16S rRNA gene sequences. Based on phylogenetic analysis (<98.65% sequence similarity), approximately 49% of total isolates represented potentially novel species or genus. Among them, extracellular protease, lipase, and exopolysaccharide activities at $10^{\circ}C$ or $20^{\circ}C$ were detected in approximately 46%, 25%, and 32% of the strains, respectively. Forty-three isolates produced at least one type of extracellular material and 21 of them produced at least two extracellular protease, lipase, and/or exopolysaccharides. Our findings indicate that culturable bacterial diversity present within the marine sediments of Ross Sea, Antarctica may contribute to the hydrolysis of the major organic constituents which is closely related with carbon and nitrogen cycling in this environment.

• Journal of the Korean GEO-environmental Society
• /
• v.12 no.6
• /
• pp.25-34
• /
• 2011

Dredged and reclaimed ground in progress at the West Coast has a high content of coarse particles. There will be different behaviors depending on the location of outlet and engineering properties of soil when its ground is dredged by a pump. Therefore, the experiments were conducted that were manufactured about the chamber equipment of length 2,650mm, width 770mm, height 735mm, experimented step filling method and water content about 300%, 500% and 700% respectively with SM and ML samples in order to realize segregating sediment characteristics of dredged ground with changing much fine. With results of analysis, ML sample by higher initial water content was reached to the period of complete sedimentation and coefficient of sedimentation consolidation increased with increases of diffusion distance. SM samples showed behavior of coarse soil with diffusion distance 120cm, diffusion distance of more than 120cm showed a similar tendency with ML sample under the influence of fines. In ML sample, it could be also found that lower depth and the more increasing diffusion distance increase in percentage of sieve #200 but water content decreases. In SM sample, it could be also found that coarse soil was piled at near the diffusion distance zone but fine soil was piled at the far diffusion distance zone and prominent difference showed between percentage of sieve #200 and water content(%) by boundary point 120cm~160cm of both samples. Also, shear strength was expressed ML-maximum 2.97kPa, SM-maximum 10.2kPa with diffusion distance.

• Proceedings of the KAIS Fall Conference
• /
• 2004.06a
• /
• pp.270-274
• /
• 2004

군포시는 인구 27만 376명(2001)의 도시로서 녹지지역, 공업지역, 주거지역, 상업지역이 혼재되어 있는 복합기능의 기존 도시지역과 최근의 도시계획에 의하여 도시기능들이 분리되어 있는 신도시지역으로 구성되어 있어서 전체적으로 복합도시의 성격을 갖고 있다. 이러한 특성으로 인하여 지역별 환경오염의 정도가 다르게 나타나고 있다. 따라서 본 연구는 군포시 환경현황을 알아보기 위해 17개 지점의 퇴적토와 16개 지점의 약수터를 선정하여 군포시의 환경문제 가운데 하상퇴적물과 음용수로 사용하고 있는 약수터의 수질환경 변화를 월별로 비교$\cdot$분석하였다. 그 결과 휘발성고형물(VSS)은 도시권 영역인 당정천 지역(9,10)에서 높은 농도를 보였으며, 영양염류의 지표인 총질소(T-N)와 총인(T-P)의 경우 생활하수의 직접적인 영향을 받고 있는 15지점이 T-N 12.2mg/kg, T-P 6.09mg/kg의 농도를 보이고 있으며 중금속의 농도는 공업지역 부근인 3,9,10지점에서 납의 농도가 다른 중금속에 비하여 높은 것으로 조사되었다. 약수의 경우 모든 음이온 항목이 먹는물 수질기준을 만족하고 있으므로 건강상 유해한 영향이나 심미적인 영향을 미치지 않을 것으로 사료된다.

• The Journal of the Petrological Society of Korea
• /
• v.19 no.1
• /
• pp.89-101
• /
• 2010

To constrain the depositional ages of the Gyeongsang sedimeantary formations, SHRIMP U-Pb ages were determined from detrital zircons in three samples: (1) a pebble-bearing sandstone from the lowermost Jinju Formation of the Sindong Group and (2) two conglomerates from the Silla Conglomerate of the Hayang Group. Their concordia ages are $112.4{\pm}1.3(2{\sigma})$ Ma and $110.4{\pm}2.0(2{\sigma})$ Ma respectively. Such ages represent the maximum deposition ages for the lowermost Jinju Formation and Silla Conglomerate, indicating the deposition of the Jinju Formation started from late Aptian and lasted to early Albian, then deposition of the rather thin Chilgok Formation and Silla Conglomerate was followed during the Albian. The age distribution of the analyzed detrital zircons indicates the presence of protoliths, or zircons derived from them, regarding a wide span of igneous activities from Mesozoic to Archean. Among such ages, there are Mesoproterozoic, Neoproterozoic and Paleozoic igneous activities, which have not been known or seldom reported from Korean peninsula. These ages further suggest the possible presence of rocks with such ages during the deposition periods or their derivation through a long river system developed into the continents at the time of deposition.

• Microbiology and Biotechnology Letters
• /
• v.30 no.2
• /
• pp.162-166
• /
• 2002

Two bithiazole-type antibiotics were isolated from the culture broth of a Myxococcus species which isolated from the marine sediment off the coast of Cheju Island, Korea. The structures of these metabolites were determined as KR025 and melithiazole F, previously reported bithiazoles, using combined spectroscopic methods. Both compounds showed an antifungal activity. In in vivo tests, these compounds exhibited potent controlling activities against tomato late blight, wheat leaf rust, and barley powdery mildew with control values more than 80% at a concentraton of 20 $\mu\textrm{g}$/ml.

• Korean Journal of Microbiology
• /
• v.45 no.1
• /
• pp.58-62
• /
• 2009

From the course of screening of useful enzyme producing microorganism from marine sedimentary layer, we isolated 2 lipase producing strains and their lipase producing activities were tested. 16S rDNA sequence analysis showed that they were Gram-positive bacteria grouped on Janibacter sp. An excellent lipase producing strain, Janibacter sp. LI-68 and J. sp. LI-80 identified by 16S rDNA analysis and biochemical methods (BIOLOG), was further studied its lipase producing characteristics. The optimum initial pH, temperature and the optimum cultral time for the enzyme production on MA medium were 8, $30{\sim}40^{\circ}C$ and 96 h, respectively.