• Journal of the Semiconductor & Display Technology
• /
• v.12 no.2
• /
• pp.1-6
• /
• 2013

The effects of interlayer formation and thermal treatment on the field-emission properties of carbon nanotubes (CNTs) were investigated. The CNTs were prepared on tungsten (W) micro-tip substrates using the electrophoretic deposition (EPD) method. The interlayers, such as aluminum (Al) and hafnium (Hf) were coated on the W-tips prior to CNT deposition and after the deposition of CNTs all the species were thermally treated at $700^{\circ}C$ for 30 min. The field-emission properties of CNTs were significantly improved by thermal treatment. The threshold electric field for igniting the electron emission was decreased and the emission current was increased. The Raman spectroscopy results indicated that this was attributed mainly to the enhancement of CNTs by thermal treatment. Also, the CNTs deposited on the interlayers showed the remarkably improved results in the long-term emission stability, especially when they were thermally treated. The X-ray photoelectron spectroscopy (XPS) measurement confirmed that this was resulted from the formation of the additional cohesive forces between the CNTs and the underlying interlayers.

• Korean Journal of Soil Science and Fertilizer
• /
• v.47 no.6
• /
• pp.457-463
• /
• 2014

This study was carried out to find out major factors to mitigate carbon emission using Life Cycle Assessment (LCA). System boundary of LCA was confined from sowing to packaging during vegetable production. Input amount of agri-materials was calculated on 2007 Income reference of white radish, chinese cabbage and chive produced at open field and film house published by Rural Development Administration. Domestic data and Ecoinvent data were used for emission factors of each agri-material based on the 1996 IPCC guideline. Carbon footprint of white radish was 0.19 kg $CO_2kg^{-1}$ at open fields, 0.133 kg $CO_2kg^{-1}$ at film house, that of chinese cabbage was 0.22 kg $CO_2kg^{-1}$ at open fields, 0.19 kg $CO_2kg^{-1}$ at film house, and that of chive was 0.66 kg $CO_2kg^{-1}$ at open fields and 1.04 kg $CO_2kg^{-1}$ at film house. The high carbon footprint of chive was related to lower vegetable production and higher fuel usage as compared to white radish and Chinese cabbage. The mean proportion of carbon emission was 35.7% during the manufacturing byproduct fertilizer; white radish at open fields was 50.6%, white radish at film house 13.1%, Chinese cabbage at outdoor 38.4%, Chinese cabbage at film house 34.0%, chive at outdoor 50.6%, and chive at film house 36.0%. Carbon emission, on average, for the step of manufacturing and combustion accounted for 16.1% of the total emission; white radish at open fields was 4.3%, white radish at film house 15.6%, Chinese cabbage at open fields 6.9%, Chinese cabbage at film house 19.0%, chive at open fields 12.5%, and chive at film house 29.1%. On the while, mean proportion of carbon footprint for the step of $N_2O$ emission was 29.2%; white radish at open fields was 39.2%, white radish at film house 41.9%, Chinese cabbage at open fields 34.4%, Chinese cabbage at film house 23.1%, chive at open fields 28.8%, and chive at film house 17.1%. Fertilizer was the primary factor and fuel was the secondary factor for carbon emission among the vegetables of this study. It was suggested to use Heug-To-Ram web-service system, http://soil.rda.go.kr, for the scientific fertilization based on soil testing, and for increase of energy efficiency to produce low carbon vegetable.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.16 no.1
• /
• pp.837-844
• /
• 2015

The purpose of this paper is to suggest the method of creation and management of urban green field based on carbon emission reduction. For a case study, Daejeon Metropolitan City in Korea was chosen. For the study, the relevant concepts of green field and carbon emission plans are reviewed as a theoretical research, and current problems of the urban green field are surveyed focused on metropolitan cities in Korea. Implementation plans of park and green in Daejeon Metropolitan City were analysed in the aspect to carbon emission reduction, climate change responding and urban green field expansion. Finally, as a result of the study, the method of creation and management of urban green field based on carbon emission reduction in the perspectives of urban structure change, green field network, conservation of green field and relevant institutions are suggested.

• Korean Journal of Organic Agriculture
• /
• v.20 no.4
• /
• pp.475-490
• /
• 2012

Since 1997, Korean Ministry of Knowledge Economy and Ministry of Environment have established data on some 400 basic raw and subsidiary materials and process like energy, petro-chemical, steel, cement, glass, paper, construction materials, transportation, recycling and disposal etc by initiating establishment of LCI database. Regarding agriculture, Rural Development Administration has conducted establishment of LCI database for major farm products like rice, barley, beans, cabbage and radish etc from 2009, and released that they would establish LCI database for 50 items until 2020 later on. The domestic LCI database for seeds, seedling, agrochemical, inorganic, fertilizer and organic fertilizer etc is only at initial stage of establishment, so overseas LCI databases are brought and being used. However, since the domestic and overseas natural environments differ, they fall behind in reliability. Therefore, this study has the purpose to select organic farming materials, survey the production process for various types of organic farming materials and establish LCI database for the effects of greenhouse gas emitted by each crop during the process. As for selecting methods, in this study organic farming materials were selected in the method of direct observation of material and bottom-up method a survey method with focus on the organic farming materials admitted into rice production. For the basic unit of carbon emission amount by the production of 1kg of organic farming material, the software PASS 4.1.1 developed by Korea Accreditation Board under Ministry of Knowledge Economy was used. The study had the goal to ultimately provide basic unit to calculate carbon emission amount in executing many institutions like goal management system and carbon performance display system etc in agricultural sector to be conducted later on. As a result, emission basic units per 1kg of production were calculated to be 0.04968kg-$CO_2$ for oystershells, 0.004692kg-$CO_2$ for expanded rice hull, and 1.029kg-$CO_2$ for bordeaux mixture liquid.

• Journal of Climate Change Research
• /
• v.8 no.4
• /
• pp.393-399
• /
• 2017

According to the United Nations Framework Convention on Climate Change (UNFCCC), all parties have to submit the national GHG inventory report. Estimating carbon stocks and changes in Land Use, Land-Use Changes and Forestry (LULUCF) needs an activity data and emission factors. So this study was conducted to develop carbon emission factor for Robinia pseudoacacia L., Betula platyphylla var. japonica, and Liriodendron tulipifera. As a result, the basic wood density ($g/cm_3$) was 0.64 for R. pseudoacacia, 0.55 for B. platyphylla, and 0.46 for L. tulipifera. Biomass expansion factor was 1.47 for R. pseudoacacia, 1.30 for B. platyphylla, and 1.24 for L. tulipifera. Root to shoot ratio was 0.48 for R. pseudoacacia, 0.29 for B. platyphylla, and 0.23 for L. tulipifera. Uncertainty of estimated emission factors on three species ranged from 3.39% to 27.43% within recommended value (30%) by IPCC. We calculated carbon stock and change using these emission factors. Three species stored carbon in forest and net $CO_2$ removal was $1,255,398\;t\;CO_2/yr$ during 5 years. So we concluded that our result could be used as emission factors for national GHG inventory report on forest sector.

• Journal of The Korean Society of Agricultural Engineers
• /
• v.65 no.5
• /
• pp.69-80
• /
• 2023

Carbon neutrality in agriculture can be derived from systematic GHG reduction policies based on quantitative environmental impact analysis of GHG-emitting activities. This study is to explore how to advance the calculation of carbon emissions from agricultural activities to the detailed spatial level to a spatial Tier 3 level (Tier 2.5 level), methodologically beyond the Tier 2 approach. To estimate the GHG emissions beyond the Tier 2.5 level by region for detailed spatial units, we constructed available activity data on carbon emission impact factors such as rice cultivation, agricultural land use, and livestock. We also built and verified detailed data on emission activities at the field level through field surveys. The GHG emissions were estimated by applying the latest national emission factors and regional emission factors according to the IPCC 2019 GL based on the field-level activity data. This study has significance that it explored ways to build activity data and calculate GHG emissions through statistical data and field surveys based on parcels, one of the smallest spatial units for regional carbon reduction strategies. It is expected that by utilizing the activity data surveyed for each field and the emission factor considering the activity characteristics, it will be possible to improve the accuracy of GHG emission calculation and quantitatively evaluate the effect of applying reduction policies.

• Journal of the Korean housing association
• /
• v.23 no.4
• /
• pp.11-18
• /
• 2012

The amount of energy consumption in the buildings is approximately 20% of domestic energy consumption. The Carbon Point Program have been published on reduction of greenhouse gas emission in buildings under the paradigm of 'Low Carbon Green Growth'. This study focuses on the effect of 'Carbon Point Program' for residential buildings in Daegu. The amount of electricity and waterwork consumption and information of households were investigated to analyse the effect of carbon point program. The samples are situated in Deagu and are apartment in Bukgu and Suseonggu. The $CO_2$ emission is analysed by factors of energy resource and household organization between before participating and after participating in Carbon Point Program. The participation type has a difference of voluntary participation in Suseonggu and passive participation in Bukgu. Based on this investigation, average amount of $CO_2$ emission was reduced from voluntary participation households but all of them did not. To promote the effect of Carbon Point Program, this study proposes that needing the plans to raise will and activity of reducing carbon and to help participation which have disadvantage against achieving reduction.

• Transactions of the Korean hydrogen and new energy society
• /
• v.35 no.1
• /
• pp.1-13
• /
• 2024

Hydrogen is emerging as an essential material for carbon neutrality. In particular, Korea needs 22.9 million tons of imported clean hydrogen by 2050 to achieve carbon neutrality. However, a large amount of carbon is emitted during the import process, and market regulations are being discussed. This research estimates the carbon emissions of importing green hydrogen from Vietnam, Australia, and the United Arab Emirates to Korea, and calculates imported green hydrogen prices under carbon emission market regulations.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.59 no.4
• /
• pp.743-748
• /
• 2010

Boron nitride (BN) and carbon nitride (CN) films, which have relatively low work functions and commonly exhibit negative electron affinity behaviors, were coated on carbon nanotubes (CNTs) by magnetron sputtering. The CNTs were directly grown on metal-tip (tungsten, approximately 500nm in diameter at the summit part) substrates by inductively coupled plasma-chemical vapor deposition (ICP-CVD). The variations in the morphology and microstructure of CNTs due to coating of the BN and CN films were analyzed by field-emission scanning electron microscopy (FE-SEM). The energy dispersive x-ray (EDX) spectroscopy and Raman spectroscopy were used to identify the existence of the coated layers (CN and BN) on CNTs. The electron-emission properties of the BN-coated and CN-coated CNT-emitters were characterized using a high-vacuum field emission measurement system, in terms of their maximum emission currents ($I_{max}$) at 1kV and turn-on voltage ($V_{on}$) for approaching $1{\mu}A$. The results showed that the $I_{max}$ current was significantly increased and the $V_{on}$ voltage were remarkably reduced by the coating of CN or BN films. The measured values of $I_{max}-V_{on}$ were as follows; $176{\mu}A$-500V for the 5nm CN-coated emitter and $289{\mu}A$-540V for the 2nm BN-coated emitter, respectively, while the $I_{max}-V_{on}$ of the as-grown (i.e., uncoated) emitter was $134{\mu}A$-620V. In addition, the CNT emitters coated with thin CN or BN films also showed much better long-term (up to 25h) stability behaviors in electron emission, as compared with the conventional CNT emitter.

• 한국정보디스플레이학회:학술대회논문집
• /
• 2007.08a
• /
• pp.475-478
• /
• 2007

A solution for carbon nanotube based field emission displays has been designed and built. The solution makes use of structure layout to control electron beam trajectories, uniformity by use of ballasting, emission anomalies eliminated by selective carbon nanotube growth and invisible spacers to maintain the vacuum gap.