• Ecology and Resilient Infrastructure
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• v.7 no.4
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• pp.284-293
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• 2020

We present a quantitative survey of the carbon storage and absorption capacity of tree species in the vegetation conservation and ecological restoration areas of Bulamsan urban nature park in Nowon-gu, Seoul. The density of the sawtooth oak (Quercus acutissima) community in the ecological conservation area is approximately 30 individuals/225 ㎡, while a further 20 species, such as Japanese snowbell (Styrax obassia), galcham oak (Quercus aliena), Asian Sweetleaf (Symplocos chinensis f. pilosa), East Asian ash (Fraxinus rhynchophylla), and Korean rhododendron (Rhododendron mucronulatum) are sparsely distributed. In contrast, the ecological restoration sites typically comprised Mongolian oak (Quercus mongolica), jolcham oak (Quercus serrata), and East Asian ash (Fraxinus rhynchophylla) plantations, with planting densities of 8.3, 7.7, and 14.3 individuals/25 ㎡ , respectively. Approximately 10 species, including Amur maple (Acer tataricum subsp. ginnala), Korean mountain ash (Sorbus alnifolia), Japanese spice bush (Lindera obtusiloba), and Korean rhododendron (Rhododendron mucronulatum) were identified in the ecologically restored area. The total amounts of carbon stored by the trees in the vegetation conservation and ecological restoration sites are 250.77 and 19.3 t C ha-1, respectively, and the total annual carbon uptakes are 10.28 and 2.33 t C ha-1 yr-1, respectively. The survey results are expected to provide important basic data for monitoring the carbon absorption capacity and carbon balance of green areas in the city.

• Journal of Korean Society for Geospatial Information Science
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• v.18 no.4
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• pp.119-129
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• 2010

The joint use of remotely sensed data and field measurements has been widely used to estimate aboveground carbon stock in many countries. Recently, Korea Forest Research Institute has developed new carbon emission factors for kind of tree, thus more accurate estimate is possible. In this study, the aboveground carbon stock of Danyang area in South Korea was estimated using k-Nearest Neighbor(kNN) algorithm with the 5th National Forest Inventory(NFI) data. Considering the spectral response of forested area under the climate condition in Korea peninsular which has 4 distinct seasons, Landsat TM seasonal satellite images were collected. As a result, the estimated total carbon stock of Danyang area was ranged from 3542768.49tonC to 3329037.51tonC but seasonal trends were not found.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.8 no.2
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• pp.78-93
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• 2003

To investigate seasonal variation and structure of the microbial community in Kyeonggi Bay, abundance and carbon biomass of nano-and micrzooplankton were evaluated in relation to size fractionated chlorophyll-a concentration, through the monthly interval sampling from December 1997 to November 1998. Communities of nano-and microzooplankton were classified into 4 groups such as heterotrophic nanoflagellate(HNF), ciliates, heterotrophic dinoflagellates(HDF) and zooplankton nauplii. Abundance and carbon biomass of HNF ranged from 380 to 4,370 cells ml-1(average 1,340$\pm$130 cells ml-1) and from 0.63 to 12.4 $\mu\textrm{g}$C 1-1(average 4.35$\pm$0.58 $\mu\textrm{g}$C 1-1), respectively. Abundance and carbon biomass of ciliates ranged from 331 to 44,571 cells ml-1(average 3,526$\pm$544 cells ml-1) and from 1.3 to 119.7 $\mu\textrm{g}$C 1-1(average 13.7$\pm$3.0 $\mu\textrm{g}$C 1-1), respectively. Abundance and carbon biomass of HDF ranged from 88 to 48,461 cells 1-1(average 9,034$\pm$2,347 cells 1-1) and from 0.05 to 54.05 $\mu\textrm{g}$C 1-1(average 6.9$\pm$2.4 $\mu\textrm{g}$C 1-1), respectively. Abundance and carbon biomass of zooplankton nauplii ranged from 5 to 546 indiv. 1-1(average 83$\pm$15 indiv. 1-1) and from 0.17 to 43.2 $\mu\textrm{g}$C 1-1(average 6.3$\pm$1.2 $\mu\textrm{g}$C 1-1), respectively. Eash component of microbial biomass was not different from tidal cycle except tintinnids group. Depth integrated nano-and microzooplankton biomass ranged from 124 to 1,635 mgC m-2(average 585$\pm$110 mgC m-2) and was highest in March and May. The relative contribution of each component to the nano-and microzooplankton showed difference according to seasons. Community structure of nano-and microzooplankton was dominated by planktonic ciliate group. During the study period, carbon biomass of nano-and microzooplankton was strongly positively correlated with size fractionated chlorophylla-a. It implied that prey-predator relationship between microzooplankton and phytoplankton was important in the pelagic ecosystem of Kyeonggi Bay.

• Resources Recycling
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• v.23 no.1
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• pp.40-47
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• 2014

Feasibility of utilizing unburned carbon residue in coal ash as a potential precursor for the production of activated carbon was assessed to seek for solution to recycle unburned carbon residue. The unburned carbon concentrate generated from the 4 stages of cleaner flotation has a grade of 87% carbon. The crystalline impurities in the concentrate included quartz and mullite. Unburned carbon had a low specific surface area of $10m^2/g$, which might be related to a high degree of coalification of domestic anthracite coal. Carbon particles were mostly porous and have a turbostratic structure. When 1g of carbon was activated with 6g of KOH powder, the highest specific surface area value of $670m^2/g$ was achieved. Low wettability of unburned carbon particles, which was resulted from high temperature combustion in a boiler, might cause poor pore formation when they were activated by KOH solution. The activated carbon produced in this study developed micropores, with an equivalent quality of general-purpose activated carbon made from coal. Hence, it is concluded that chemically treated unburned carbon can be used for water purification or an alternative to carbon black as it is.

• Transactions of the Korean Society of Mechanical Engineers
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• v.12 no.5
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• pp.1104-1112
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• 1988

In this study the structure of a two phase detonation has been numerically investigated through the assumption of a steady and one-dimensional flow in the suspension of carbon particles and pure oxygen. The bow shock formation in front of carbon particles has been taken into consideration when the relative velocity of gas flow with respect to the particle exceeds the local speed of sound. But its effect was found to be very limited to the induction zone only. Furthermore the interior particle temperature distribution has been considered in this work. It was found that the inner temperature gradient was very steep in the region of high relative velocity. On the while the temperature distribution inside the particle was almost uniform in the region of low relative velocity. Overall, the effect of the interior particle temperature distribution has been significant in the two phase detonation.

• Applied Chemistry for Engineering
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• v.25 no.4
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• pp.346-351
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• 2014

With the world population's continuous growth and urban industrialization, capacitive deionization (CDI) has been proposed as a next-generation water treatment technology to augment the supply of water. As a future water treatment method, CDI attracts significant attention because it offers small energy consumption and low environmental impact in comparison to conventional methods. Carbon electrodes, which have large surface area and high conductivity, are mainly used as electrode materials of choice for the removal of ions in water. A variety of carbon materials have been investigated, including their adsorption-desorption behavior in accordance to the specific surface area and pore size distribution. In this review, we analyzed and highlighted these carbon materials and looked at the impact of pore size distribution to the overall CDI efficiency. Finally, we propose an optimal condition in the interplay between micropores and mesopores in order to provide the best electrosorption property for these carbon electrodes.

• Proceedings of the Korean Environmental Sciences Society Conference
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• 2008.11a
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• pp.306-309
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• 2008

본 연구에서는 순천만(전남 순천시 해룡면 농주리) 연안습지에서 온도(퇴적물/대기), 퇴적물 내 유기탄소 및 대기 중 이산화탄소의 관계에 대해 분석하였다. 현장관측은 2008년 3월 16일11시부터 15시 사이에 수행되었으며, 약 300 m X 100 m의 갯벌 지역 내 30개 지점에서 조사되었다. 퇴적물과 대기의 온도와 대기 중 이산화탄소량은 현장에서 측정되었으며, 각 지점에서 채취된 퇴적물 내 유기탄소량은 부경대학교 공실관에서 TOC Analyzer를 이용하여 분석되었다. 퇴적물과 대기 중의 온도는 각각 13.2$\sim$17.5$^{\circ}C$ 및 15.0$\sim$18.9$^{\circ}C$의 범위이었으며, 평균은 15.65$^{\circ}C$와 17.51$^{\circ}C$로서 대기 온도가 약 2$^{\circ}C$ 정도 높았다. 대기 중 이산화탄소량은 퇴적물 직상부, 상부 0.5 m 및 1.0 m의 3개 지점에서 측정되었다. 각 지점별 평균 이산화탄소량은 퇴적물 직상부 352 ppm, 상부 0.5 m 지점 355 ppm, 상부 1.0 m 지점 363 ppm으로서 거의 유사하였으나, 퇴적물에서 상부로 갈수록 약간 증가하는 경향을 보였다. 대기 중 이산화탄소량의 분산은 퇴적물 직상부와 상부 0.5 m 지점에 비해 상부 1.0 m 지점에서 약 3배 정도 높게 나타났으며, 이는 주변 대기의 영향에 의한 것으로 판단된다. 현장에서 채취된 퇴적물 내 유기탄소량은 0.60$\sim$1.12%의 범위이었으며, 평균은 0.72% 이었다. 유기탄소량의 분산은 0.01로서 매우 낮았으며, 또한 1개 지점(1.12%)을 제외하면 유기탄소량의 범위는 0.60$\sim$0.82% 정도로서 연구지역 내 유기탄소량의 공간적인 분포가 비교적 균질함을 알 수 있었다. 본 연구를 통해, 대기 중 이산화탄소량은 온도효과와 주변 대기와의 혼합 정도에 따라 영향을 받고 유기탄소는 이러한 영향성이 적었음을 알 수 있었다.

• 대한공업교육학회지
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• v.32 no.2
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• pp.188-198
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• 2007

Platinum nanoparticles loading on carbon nanotube was carried out by impregnation of hexachloro platinate(IV) from hydrogen hexachloro platinate(IV) hydrate dissolved solution without using reduction agents, and heating the hexachloro platinate(IV) impregnated carbon nanotube up to $400^{\circ}C$. The amounts of impregnated hexachloro platinate(IV) on to carbon nanotube were measured with UV-visible spectrophotometer. The TG, XRD, and TEM analysis were performed to confirm the platinum particles loading and distribution on carbon nanotube. The average platinum particles size on carbon nanotube was under 2 nm by heating the hexachloro platinate(IV) up to $400^{\circ}C$ in spite of non-using reduction agents, while the average size increased due to the agglomeration of some particles by heating them up to $800^{\circ}C$. Therefore, uniformly distributed platinum nanoparticles loading on carbon nanotube can be obtained from simple impregnation of hexachloro platinate(IV) from solution and heating it up to $400^{\circ}C$.

• Geotechnical Engineering
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• v.14 no.6
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• pp.81-92
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• 1998

A beam on elasto-plastic foundation modeling of soldier pile and woodlagging tieback walls or anchored walls was developed and tested. An instrumented full scale tieback wall in sand was constructed at the National Geotechnical Experimentation Bite located on Texas A&M University. The experimental earth pressure deflection relationship (p-y curves) was developed from the measurements. The construction sequence was simulated in the proposed method. The conceptual methodology of an anchored wall design was introduced by using the proposed method. The proposed method was evaluated with the measurements of case histories in sand and clay. A parametric research was performed to study the most influencing factors for the proposed method. It is concluded that the proposed method represents a significant improvement on the prediction of bending moments and deflections of the properly designed walls.

• Composites Research
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• v.33 no.4
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• pp.198-204
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• 2020

In this study, we employ the full atomistic molecular dynamics simulation and finite element homogenization method to predict the thermo-mechanical properties of nanocomposites including carbon nanotube bundle. As the number of carbon nanotubes within the single bundle increases, the effective in-plane Young's modulus and in-plane shear modulus decrease, and in-plane thermal expansion coefficient increases, despite the same volume fraction of carbon nanotubes. To investigate the thickness of interphase zone, we employ the radial density distribution. It is investigated that the interphase thickness is almost independent on the number of carbon nanotubes within the single bundle. It is assumed that the matrix and interphase are isotropic materials. According to the predicted thermo-mechanical properties of interphase zone, the Young's modulus and shear modulus of interphase zone clearly decrease, and the thermal expansion coefficient increases. Based on the thermo-mechanical interphase behavior, we developed the multiscale homogenization model to predict the thermo-mechanical properties of PLA nanocomposites that include the carbon nanotube bundle.