• Carbon letters
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• v.10 no.3
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• pp.202-207
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• 2009

Pitch-based carbon fiber tows were prepared from naphtha cracking bottom oil by reforming and carbonization. The relationship between exothermic heat and carbon contents of the fiber was investigated by changing the carbonization conditions. The carbon contents and the crystallinities of isotropic pitch-based carbon fibers were 86.8~93.8 wt% and 33.7~40.1%, respectively, which were linearly proportional to the increase of carbonization temperature from 700 to $1000^{\circ}C$. The exothermic heat (temperature increase) of fiber tows was measured in a short time, which was also linearly proportional to the increase of carbon contents due to the increase of crystallinity, even though the crystallinity was low. Therefore, the carbon contents or carbonization degree of fibers can rapidly and indirectly be estimated by measuring the surface temperature increase of fibers.

• Korean Journal of Soil Science and Fertilizer
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• v.50 no.1
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• pp.65-70
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• 2017

Soil was regarded as infinite resources but recently, soil is considered as invaluable resources that we need to protect and conserve. Main objective of this research was to evaluate soil value in terms of soil carbon contents. Soil was classified into forest, paddy, upland, and grass. Carbon contents in each soil was calculated based on soil chemical properties. Calculated soil carbon contents was ranged $15.31-108.86mg\;kg^{-1}$. Based on soil carbon contents, soil value was assumed adapting economic concepts. Calculated total soil value based on soil carbon contents was about 18.46 trillion won. Among others, carbon contents in forest was the highest and value was assumed 11.95 trillion won followed by paddy field (3.7 trillion won).

• 한국연소학회:학술대회논문집
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• 2015.12a
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• pp.99-102
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• 2015

To operate coal fired power plant efficiently is considered unburned carbon as important factor. But, unburned carbon contents change does not have an impact on Boiler performance simultaneously. we evaluated that unburned carbon contents change had an little influence on unburned carbon loss change for performance side at a real power plant.

• Korean Journal of Environmental Agriculture
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• v.7 no.2
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• pp.136-145
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• 1988

To investigate the seasonal changes of various organic and inorganic compounds in compost, carbon compounds in compost were analyzed at various composting periods. Contents of organic matter, cellulose, total carbon, organic carbon and biodegradable carbon in compost were decreased with the progress of composting. In contrast, contents of lignin and nonbiodegradable carbon were increased a little with the progress of composting, but effective contents of lignin were decreased with the lapse of composting time, while effective contents of nonbiodegradable carbon were not changed. Total carbon contents in organic matter in compost were decreased within 9 weeks after composting, and then increased thereafter. Difference between average values of total and biodegradable carbon contents was 6.2%. Actual decay rates of all the carbon compounds were higher than decay rates of the compounds at all the experimental periods. Both of actual decay rate and decay rate of all the carbon compounds were increased rapidly within 2 weeks after composting, and thereafter the rates were increased slightly with the lapse of composting time. Especially the decay rates of cellulose were increased from 9 to 21 weeks after composting. Actual degradation capacity showed the same tendency to degradation capacity of all the carbon compounds in compost. Decay rate and degradation capacity of lignin in compost had minus values, while actual decay rate and actual degradation capacity had plus values. Highly positive correlations were observed among organic matter, cellulose, total carbon and biodegradable carbon one another. Nonbiodegradable carbon showed highly negative correlation with organic matter, cellulose, total carbon, organic carbon and biodegradable carbon, respectively. The same tendencies were observed between lignin and organic matter, cellulose, total carbon, organic carbon and biodegradable carbon. Highly positive correlation was observed between lignin and nonbiodegradable carbon in compost.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.10 no.6
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• pp.62-69
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• 2007

This study has been carried out to estimate aboveground carbon contents in an average 30-years-old Betula platyphylla and 32-years-old Juglans mandshurica stands in Chungju, Chungbuk Province. Nine sample trees were cut in each forest and soil samples were collected. Carbon concentration in stemwood, stembark, branch, and foliage were ranged from 54.6% to 57.0% in Betula platyphylla and 53.5% to 56.9% in Juglans mandshurica stands. Aboveground carbon contents was estimated by the equation model logWt=A+BlogD where Wt is oven-dry weight in kg and D is DBH in cm. Total aboveground carbon contents was 34.31t/ha in Betula platyphylla stand and 21.10t/ha in Juglans mandshurica stand. Aboveground net primary carbon production was estimated at 2.31t/ha/yr in Betula platyphylla stand and 2.03t/ha/yr in Juglans mandshurica stand.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.26 no.12
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• pp.924-927
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• 2013

In this study, we proposed CMP-PLAs to replace the Al heat sinks as heat sink materials, and investigated heat dissipation characteristics of the LED lighting devices using them. The crystallinity of the proposed CMP-PLA heat sinks decreased with increasing carbon nanotube contents in CMP-PLA. However, the thermal conductivity was improved with the increase of the carbon nanotube contents. The heat dissipation characteristics of the LED lighting devices using CMP-PLA heat sinks was improved with increasing carbon nanotube contents in CMP-PLA. For the LED lighting devices using CMP-PLA heat sinks with 40% carbon nanotube contents, the initial temperature measured at the heat sink plate was $27^{\circ}C$, which increased as time, and it was saturated around $56^{\circ}C$ after an hour. The LED lighting devices using CMP-PLA heat sinks are expected to be functional materials that can reduce their weight and improve their electric properties, compared to those using existing Al heat sinks.

• Journal of Korean Society for Atmospheric Environment
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• v.31 no.4
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• pp.368-377
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• 2015

Bunker C fuel oil is a high-viscosity oil obtained from petroleum distillation as a residue. The sulfur content of bunker C fuel oil is limited to 4.0% or even lower to protect the environment. Because bunker C fuel oil is burned in a furnace or boiler for the generation of heat or used in an engine for the generation of power, carbon dioxide is emitted as a result of combustion. The objective of this study is to investigate $CO_2$ emission characteristics of bunker C fuel oil by sulfur contents. Calorific values and carbon contents of the fuels were measured using the oxygen bomb calorimeter method and the CHN elemental analysis method, respectively. Sulfur and hydrogen contents, which were used to calculate the net calorific value, were also measured and then net calorific values and $CO_2$ emission factors were determined. The results showed that hydrogen content increases and carbon content decreases by reducing sulfur contents for bunker C fuel oil with sulfur contents less than 1.0%. For sulfur contents between 1.0% and 4.0%, carbon content increases as sulfur content decreases but there is no evident variation in hydrogen content. Net calorific value increases by reducing sulfur contents. $CO_2$ emission factor, which is calculated by dividing carbon content by net calorific value, decreases as sulfur content decreases for bunker C fuel oil with sulfur contents less than 1.0% but it showed relatively constant values for sulfur contents between 1.0% and 4.0%.

• Journal of the Korean Society of Tobacco Science
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• v.27 no.1 s.53
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• pp.68-74
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• 2005

Glycerol triacetate(triacetin) is the currently used common plasticizer in the making filters from cellulose acetate tow. For the mono acetate filter, the determination of triacetin contents is already established by CORESTA recommended method (No. 59). But unfortunately, the analytical method of triacetin in the activated carbon filter have not reported so far. In this study, it was established the analytical method of carbon filter's triacetin contents at various extraction conditions, bath ratio and internal standard materials. The confidential level appeared above $95\%$ when the extraction time, ISTD material and bath ratio was 3 hours, tripropionin and below 500 mg activated carbon / 50 $m\ell$ ethanol, respectively. Also, in the distribution of triacetin with filter materials in activated carbon filters, the triacetin amount was the most contained in activated carbon. Therefore, this method can be applied to the determination of triacetin contents in the activated carbon filter.

• Bulletin of the Korean Chemical Society
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• v.33 no.11
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• pp.3589-3592
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• 2012

Carbon composite bipolar plates with various carbon black contents were prepared by a compression molding method. The electrical conductivity and electrochemical stability of the bipolar plates have been evaluated. It is found that the electrical conductivity increases with increasing carbon black contents up to 15 wt %. When the carbon black contents are greater than 15 wt %, the electrical conductivity decreases because of a poor compatibility between epoxy resin and carbon black, and a weakening of compaction in the carbon composite bipolar plate. Based on the results, it could be concluded that there are optimum carbon black contents when preparing the carbon composite bipolar plate. Corrosion tests show that the carbon composite bipolar plate with 15 wt % carbon black exhibits better electrochemical stability than a graphite bipolar plate under a highly acidic condition. When the optimized carbon composite bipolar plate is applied to vanadium redox flow cells, the performance of flow cells with the carbon composite bipolar plate is comparable to that of flow cells with the graphite bipolar plate.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.11a
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• pp.114-115
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• 2006

In the present study we investigated effects by changing binder contents m the carbon counter electrode for dye-sensitized solar cells. Binder contents changed for 6 wt%, 7 wt%, 8 wt% before making carbon electrode. In the result of the measurement the specific resistance for 6 wt% was lowest among others And the surface of the carbon electrode which was measured by SEM was best m the 6 wt"%. The electrode properties be showing in an experiment were due to increment of surface roughness that appeared the carbon electrode, which decreased internal surface area.