• Journal of Korean Society of Environmental Engineers
• /
• v.34 no.8
• /
• pp.533-540
• /
• 2012

The concentration of organic compounds was analyzed at each step of BAC (biological activated carbon) process though BDOC (biodegradable dissolved organic carbon) total/rapid/slow. Further, bacteria communities and biomass concentrations measured DGGE (denaturing gradirnt gel electrophoresis) and ATP (adenosine triphosphate) methods were analyzed. The bed volume of steady state is different based on assessment of organic compounds removal. Bed volumes at steady state in DOC, $BDOC_{rapid}$ and $BDOC_{total/slow}$ removal were around 27,500, 15,000 and 32,000, respectively. A biomass didn't change after the bed volume reached 22,500 according to analyzing HPC (heterotrophic plate count) and ATP concentration of bacteria. The concentration of HPC and ATP were $3.3{\times}10^8$ cells/g and $2.14{\mu}g/g$, respectively. The number of the DGGE band were only 5 at the bed volume 8,916, but increased up to 11 at the bed volume 49,632. As operation time increase, bacterial group were more diversity. Four bacteria species including Pseudomonas fluorescens, the uncultured bacterium similar to Acinetobacteria, uncultured Novosphingobium sp. and Flavobacterium frigidarium have detected from the early stages and Proteobacteria group were dominantly detected.

• Korean Journal of Ecology and Environment
• /
• v.41 no.1
• /
• pp.1-10
• /
• 2008

The seasonal variations of water quality and periphyton were investigated in an artificial stream (the Cheonggyecheon Stream) flowing through the Seoul City. TP showed a longitudinal gradient: 10 to $59{\mu}gP\;L^{-1}$ in the upper stream sites, and 15 to $90{\mu}gP\;L^{-1}$ in downstream sites. POP was a major form of TP in the water, occupying over 60%, while the proportion of DIP was less than 10% except for St. 4. N/P atomic ratio ranged from 78 to 554, which implies phosphorus would limit algal growth more than nitrogen. The biomass of periphyton did not show much difference among sites, and it was relatively higher in spring and fall season $(10\sim20{\mu}gChl\;{\alpha}cm^{-2})$ and lower in August $(<5{\mu}gChl\;{\alpha}cm^{-2})$, possibly because biofilms were washed off during spates of summer monsoon. Cyanobacteria was the dominant taxon in the periphyton community throughout the year. The periphyton standing crop can be classified as a nuisance level. It seems that phosphorus level is sufficiently high even though the input water is treated chemically, and modest water velocity $(20\sim90cm\;sec^{-1})$ and rocky bottom provide optimal conditions for periphyton growth.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.13 no.1
• /
• pp.33-44
• /
• 1980

부착 생물에 관한 연구는 선박, 해수 이용시설, 수산 양식업 둥의 방제대책과 관련하여 부착 생물의 종류, 부착 량, 성장도 및 계절적 변화 둥의 연구가 중요한 문제하고 생각한다. 특히 양식시설이 밀집한 진해만 해역의 굴 양식 시설에 부착하는 대부분의 생물들이 Ascidicea, Crustacea, Cirripedia, Bivalvia, Bryozoa, Polychaeta, marine algae 등이며, 이들 가운데 피해가 심한 다모환충류에 관하여 분류학적인 연구를 시도하였던 바 수하연의 양식 굴 사이에서 많은 양의 갯지렁이류를 얻었기에 보고 한다. 수하연에 서식하는 갯지렁이류는 제2부착성(Kazihara, 1964)의 갯지렁이류로서 왕관 모양의 큰 아가미 혹은 몸앞 부분에 실모양의 감각 촉수를 가지고 굴에 피해를 입히는 짧은수술갯지렁이 Loimia medusa, 미끈꽃갯지렁이 Myxicola infundibulum와 제1부착성으로서 굴 패각, 양식 시설 등에 석회질의 집을 형성시켜 피해를 입히는 우산관덮개꽃갯지렁이 Hydroides ezoensis, 둥근구멍환덮개꽃갯지렁이 Dexiospira alveolatus 등의 7과 12속 13종을 보고한다. 이 가운데 새날개갯지렁이 Chaetopterus variopedatus와 둥근구멍관덮개꽃갯지렁이 Dexiospira alveolatus는 한국 미기록종이다.

• Journal of the Korean Recycled Construction Resources Institute
• /
• v.12 no.1
• /
• pp.1-7
• /
• 2024

Concrete, as a porous construction material, permits chloride penetration from outside, which yields corrosion in embedded steel. In the study, an accelerated corrosion technique (ICM: Impressed current method) was adopted for rapid corrosion formation with 10 Volt of potential, and corrosion amou nt was controlled u p to 10.0 %. Corrosion amou nt had a linear relationship with cumulative corrosion current and increased with a quadratic function of accelerating period due to cracking. Regarding bond strength test, OPC concrete showed rapid drop of bond strength over 3.0 % of corrosion weight ratio, however slag concrete with 30 % replacement ratio showed a level of 51.4~71.6 % of corrosion ratio to OPC concrete with keeping residual bond strength.

• Proceedings of the Korean Magnestics Society Conference
• /
• 2002.12a
• /
• pp.122-123
• /
• 2002

현재 제철소 냉연공장에서는 수지처리 강판을 생산하기 위하여 수지 coater를 사용하고 있다. 그런데 강판의 이면 피복 시, applicator roll에 대한 back-up roll의 균일 하중 부하로 수지의 균일한 피복이 실현되나, 전면을 피복할 때 하중 부하를 위한 별도의 tool이 없는 상태로 강판의 hunting에 대응 불가능한 현장 layout으로 되어 전면 수지부착량 편차가 크게 발생되었다. (중략)

• Annual Conference on Human and Language Technology
• /
• 2012.10a
• /
• pp.126-131
• /
• 2012

본 논문은 자연언어처리에 필요한 여러 언어 정보를 구축하기 위한 도구를 설계하고 구현하였다. 본 논문에서 제안한 부착 도구는 기본적으로 형태소, 구묶음, 기반구의 품사 정보를 부착하고 추가적으로 명사에 대해서는 각 요소의 의미정보를 부착한다. 또한 형태소와 구묶음의 경우에는 사전형 정보를 부착함으로써 사전 구축 등 보다 폭넓게 사용될 수 있도록 하였다. 언어정보 부착에 있어서 가장 어려운 점은 어떻게 여러 작업자들이 일관성을 유지하느냐이다. 이를 위해 본 논문에서는 각 작업자들이 다른 작업자들의 부착 결과를 쉽게 참조하여 보다 손쉽게 수정할 수 있도록 설계되었다. 또한 기존에 잘못 부착된 정보를 발견하면 이를 쉽게 고칠 수 있도록 하였으며 또한 유사한 오류를 검색할 수 있도록 하여 쉽게 수정할 수 있도록 하였다.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.26 no.6
• /
• pp.73-81
• /
• 2022

Recently, as the service life of structures increased, the load-carrying capacity of deteriorated reinforced concrete, where corrosion of reinforcing bars occurs due to various causes, is frequently decreased. In order to address this problem, many studies on the bond characteristic of FRP (Fiber Reinforced Polymer) bars with corrosion resistance, light weight and high tensile strength have been conducted, however there are not many studies on the bond characteristic of grid-typed CFRP embedded in concrete. Therefore, in order to evaluate the bond characteristics of grid-typed CFRP and its usability as a substitute for steel rebar, a pull-out test is performed using the longitudinal bond length and transverse grid length of the grid-typed CFRP as variables. Through the pull-out test, the bond load-slip curve of the grid-typed CFRP is derived, and the bond behavior is analyzed. The total bond load equation is proposed as the sum of the bond force of the longitudinal bond length and the shear force of the grid in the transverse direction. Also, expressing the area of the bond load-slip curve as total work, the change in dissipated energy with respect to the slip is analyzed to examine the effect of the tranverse grid on the bond force.

• Journal of Wetlands Research
• /
• v.13 no.3
• /
• pp.515-522
• /
• 2011

This study examined the epiphytes using stable isotopes. Separated epiphytes should represent the water quality. In study areas, where agricultural paddies were prevailing, biomass of epiphytes can increase nitrogen isotopes(${\delta}^{15}N$) and as a result decrease in carbon isotopes(${\delta}^{13}C$). Naerin stream and Inbuk upper areas showed higher nitrogen isotopes(${\delta}^{15}N$) than in Hangye and Buk stream. Also, stable carbon isotopes(${\delta}^{13}C$) in Naerin stream and Inbuk streams tended to increase than in Hangye and Buk stream. This can indicate the epiphytes can be a good indicator for water quality pollution.

• Journal of the Korea Concrete Institute
• /
• v.15 no.1
• /
• pp.17-24
• /
• 2003

One of the reasons for brittle failure in reinforced concrete structures subjected to severe earthquake is due to large local bond-slippage of bars resulting in fast bond degradation between reinforcing bars and concrete. This study aims to evaluate effects of bar deformation height on bond performance, specially, bond degradation under cyclic loading. Bond test specimens were constructed with machined bars with high relative rib areas. The degree of confinement by transverse bars is also another key parameters in this bond test. From test results, amounts of energy dissipation are calculated and compared for each parameter. Test results show that bond strength and stiffness drops significantly as cycles increases. The confinement and high relative rib area are effective to delay bond degradation, as the reduction of bond strength of cyclic loading compared to monotonic loading decreased for bars with large confinement and high relative rib areas. The energy dissipation also increases as the degree of confinement and relative rib area increases. However, tested bars with very high rib areas show that the bond may be damaged at relatively small slip because of high stiffness. The study will help to understand the bond degradation mechanism due to bar deformation height under cyclic loading and be useful to develop new deformed bars with high relative rib areas.

• Polymer(Korea)
• /
• v.38 no.6
• /
• pp.820-826
• /
• 2014

The objective of this study is to find the relationship between the tensile strength of the polymer film and the bond strength and tensile strength of the polymer-modified mortar using styrene (St) and butyl acrylate (BA), and porosity. In the test results, the bond strength and tensile strength of the polymer-modified mortar increased with increases in the tensile strength of polymer film and the fine pore volume.