• 전기학회논문지
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• 제56권1호
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• pp.147-150
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• 2007

Electro-deposition of carbon film on silicon substrate in methanol solution was carried out with various current density, solution temperature and electrode spacing between anode and cathode. The carbon films with smooth surface morphology and high electrical resistance were formed when the distance between electrode was relatively wider. The electrical resistance of the carbon films were independent of both current density and solution temperature.

• Carbon letters
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• 제16권1호
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• pp.25-33
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• 2015

The prime objective of this research was to study the influence of hot-pressing pressure and matrix-to-reinforcement ratio on the densification of short-carbon-fiber-reinforced, randomly oriented carbon/carbon-composite. Secondary objectives included determination of the physical and mechanical properties of the resulting composite. The 'hybrid carbon-fiber-reinforced mesophase-pitch-derived carbon-matrix' composite was fabricated by hot pressing. During hot pressing, pressure was varied from 5 to 20 MPa, and reinforcement wt% from 30 to 70. Densification of all the compacts was carried at low impregnation pressure with phenolic resin. The effect of the impregnation cycles was determined using measurements of microstructure and density. The results showed that effective densification strongly depended on the hot-pressing pressure and reinforcement wt%. Furthermore, results showed that compacts processed at lower hot-pressing pressure, and at higher reinforcement wt%, gained density gradually during three densification cycles and showed the symptoms of further gains with additional densification cycles. In contrast, samples that were hot-pressed at moderate pressure and at moderate reinforcement wt%, achieved maximum density within three densification cycles. Furthermore, examination of microstructure revealed the formation of cracks in samples processed at lower pressure and with low reinforcement wt%.

• Journal of Forest and Environmental Science
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• 제36권1호
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• pp.37-46
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• 2020

Vegetation carbon sequestration and regeneration are the two major parameters of forest research. In this study, we analyzed the vegetation carbon stock and regeneration of community-managed pine plantation of Kathmandu, central Nepal. Vegetation data were collected from 40 circular plots of 10 m radius (for the tree) and 1m radius (for seedling) applying a stratified random sampling and nested quadrat method. The carbon stock was estimated by Chave allometric model and estimated carbon stock was converted into CO₂ equivalents. Density-diameter (d-d) curve was also prepared to check the regeneration status and stability of the plantation. A d-d curve indicates the good regeneration status of the forest with a stable population in each size class. Diversity of trees was very low, only two tree species Pinus roxburghii and Eucalyptus citriodora occurred in the sample plots. Pine was the dominant tree in terms of density, basal area, biomass, carbon stock and CO₂ stock than the eucalyptus. The basal area, carbon stock and CO₂ stock of forest was 33±1.0 ㎡ ha^-1, 108±5.0 Mg ha^-1 and 394±18 Mg ha^-1, respectively. Seedling and tree density of the plantation was 4,965 ha^-1 and 339 ha^-1 respectively. The forest carbon stock showed a positive relationship with biomass, tree diameter, height and basal area but no relationship with tree density. Canopy cover and tree diameter have a negative effect on seedling density and regeneration. In conclusion, the community forest has a stable population in each size class, sequestering a significant amount of carbon and CO₂ emitted from densely populated Kathmandu metro city as the forest biomass hence have a potentiality to mitigate the global climate change.

• 한국주조공학회지
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• 제22권6호
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• pp.309-314
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• 2002

The effect of mold density and evacuation on surface defect of high chromium cast iron upon EPC process was investigated. Under evacuation of $0.1{\sim}0.3$ atm, surface defects were carbon defect, burn on and misrun. Carbon defect was augmented by increasing mold density from 0.011 g/$cm^3$ to 0.03 g/$cm^3$ under evacuation of $0.1{\sim}0.3$ atm, but carbon defect was decreased by increasing evacuation from 0.1 to 0.3 atm. Burn-on wasn't found under evacuation of 0.1 atm regardless of mold density, but burn-on was augmented by increasing evacuation from 0.2 to 0.3 atm and decreased by reducing mold density. Misrun was only found under 0.1 atm evacuation and 0.011 g/$cm^3$ mold density.

• 한국공작기계학회논문집
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• 제10권6호
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• pp.109-115
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• 2001

This paper investigates the mechanical characteristics of angle-ply laminates with non-woven carbon tissue. The lami- nates were made by inserting non-woven carbon tissue at the interface. Specimens were rounded near the tabs by grinding and polishing to reduce the stress concentration. Cyclic loads were applied to the specimens and the stress and fatigue life curves were obtained. The matrix crack density was also evaluated to check the effects of non-woven carbon tissue on the fracture resistance of composite laminates. C-Sean technique was used to evaluate the delamination, and SEM was used to understand the fracture mechanisms of the laminates. Experimental results show that the fatigue strength and life of composite laminates were increased by inserting non- woven carbon tissues. The results also show that the matrix crack density and delamination area were reduced by inserting non-woven carbon tissues.

• Elastomers and Composites
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• 제33권5호
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• pp.315-323
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• 1998

본 연구의 목적은 카본블랙 첨가량 변화, 가황조건 및 가황시스템 변화에 따른 배합고무의 가교밀도 및 고무보강성을 조사하고자 하였다. 결합고무량은 배합고무중 카본블랙 체적비가 증가함에 따라 증가하였으나, 총가교밀도는 결합고무량 증가에 따라 감소하였다. 가황반응 속도상수는 가황온도 및 가황시스템에 따라 현저하게 변화하였으며, 특히 가황온도에 강한 의존성을 나타내었다. 가황반응의 활성화에너지는 카본블랙 첨가량이 많고 EC 가황시스템이 적용된 배합고무 또는 카본블랙 첨가량이 적고 CC 가황시스템이 적용된 배합고무에서 높게 나타났다. 가황된 배합고무중 가장 높은 총가교밀도는 카본블랙 첨가량이 적고 가황시스템중 CC 가황시스템이 적용된 배합고무에서 나타났으며, EC 가황시스템에 의한 총가교밀도의 뚜렷한 변화는 나타나지 않았다. Mooney-Rivlin식에 의한 가장 높은 탄성상수는 카본블랙 첨가량이 적고, SEC 가황시스템이 사용된 배합고무에서 나타났다. 모듈러스는 배합고무중 카본블랙 첨가량이 증가함에 따라 증가하였으며, 가황시스템별 영향은 SEC>CC>EC 시스템 순으로 높게 나타났다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2006년도 추계학술대회 논문집 Vol.19
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• pp.388-389
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• 2006

Electro-deposition of carbon film on silicon substrate in methanol solution was carried out with various current density, solution temperature and electrode spacing between anode and cathode. The carbon films with smooth surface morphology and high electrical resistance were formed when the distance between electrode was relatively wider. The electrical resistance of the carbon films were independent of both current density and solution temperature.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 Techno-Fair 및 추계학술대회 논문집 전기물성,응용부문
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• pp.128-129
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• 2007

Electrochemical method of carbon film on silicon substrate in methanol solution was carried out with various current density, solution temperature and electrode spacing between anode and cathode. The carbon films with smooth surface morphology and high electrical resistance were formed when the distance between electrode was relatively wider. The electrical resistance of the carbon films were independent of both current density and solution temperature.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제54권12호
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• pp.558-560
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• 2005

The carbon film was deposited by the electrolysis of methanol solution. Carbon films have been grown on silicon substrates using the method of chemical process. From investigations of the Raman spectroscopy and the FTIR spectroscopy, the carbon film deposited by the electrolysis was identified the hydrogenated carbon film with the porous structure. The carbon film deposited by elctrolysis of methanol was identified as the hydrogenated carbon film with porous structure. Deposition parameters for the growth of the carbon films were current density, methanol liquid temperature. We electrical resistance and surface morphology of carbon films formed various conditions specified by deposition parameters. It was clarified that the high electrical resistance carbon films with smooth surface morphology are grown when a distance between the electrodes is relatively wider. We found that the electrical resistance in the films independent of both current density and methanol liquid temperature. The temperature dependence of the electrical resistance in the low resistance carbon films is different from one obtained in graphite..

• 한국산림과학회지
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• 제90권6호
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• pp.774-780
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• 2001

경기도 광릉 중부임업시험장내 임목밀도와 지위가 다른 31년생 리기다소나무임분올 대상으로 3개의 $20{\times}10m$ 조사구를 선정하고 5년 동안(1997~2001) 각 부위별 탄소량 및 탄소 년 증가량을 조사하였다. 각 부위별 탄소함량은 잎>가지>수피>줄기>임상>토양 0~15cm>토양 15~30cm순 이었으며 탄소저장량 및 년 증가량은 임목밀도와 지위에 따라 차이가 있는 것으로 나타났다. 유사한 임목밀도의 경우 지위가 높은 지역이 탄소저장량과 증가량이 높았으며 유사한 지위의 경우 임목밀도에 의해 탄소저장량 및 년 증가량이 차이를 보이고 있다. 조사된 임분의 임목뿌리를 제외한 리기다소나무임분의 총탄소 저장량은 140,600kgC/ha으로 임목 61%, 토양 31%, 임상 8%로 나타났다. 고사목이 많이 발생하였던 2001년도를 제외한 년 평균 탄소 증가량은 3,233kgC/ha/yr로 줄기>가지>수피>잎 순이었다. 31년생 리기다소나무임분의 탄소저장량 및 년 증가량 변화를 조사한 결과 유사한 지위에서는 임목밀도가 높은 것이 지위에 차이가 날때는 임목밀도 조절에 의한 생장량 증가가 탄소흡수능력을 증진 할 수 있을 가능성을 시사한다.