• Transactions of Materials Processing
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• v.22 no.3
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• pp.158-164
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• 2013

The spheroidization behavior of cementite in a SK85 high carbon steel was investigated in this study. Fine and coarse pearlite microstructures were obtained by appropriate heat treatments according to the TTT diagram of SK85 high carbon steel. Hot rolled plates of SK85 steel were austenitized at $800^{\circ}C$ for 2 hrs and then put directly into a salt bath at either $570^{\circ}C$ or $670^{\circ}C$ to obtain a fine pearlite (FP) structure and a coarse pearlite (CP) structure, respectively. Cold rolling was subsequently conducted on those specimens with reduction ratios from 0.2 to 0.4. Spheroidization heat treatments were conducted at the subcritical temperatures of 600 and $720^{\circ}C$ for 1 to 32 hrs to elucidate the effect of initial microstructures, heat treatment temperature, and cold reduction ratios on the cementite spheroidization rate. Spheroidization proceeded with fragmentation of cementite plates, spheroidization of the cementite platelets, and coarsening consecutively. Mechanical fragmentation of cementite by cold rolling expedited the rate of spheroidization. The spheroidization rate of FP was much more rapid than that of CP and the spheriodization rate increased with increases in the cold reduction ratio.

• Journal of the Korean Society of Tobacco Science
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• v.14 no.1
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• pp.33-41
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• 1992

These studies were conducted to investigate effects of phytohormone and activated carbon on the growth and rooting of teratoma shoots induced from Nicotiana tabacum cv. NC2326 transformed by Aerobacterium tumefaciens C58. GA was effective for shoot elongation and reduction of multiple shoots from teratoma shoot, however, leaves of teratoma shoot cultured on the medium with GA were pointed. ABA was also effective in promoting shoot elongation, but was not for reduction of multiple shoots. Teratoma shoot cultured on the medium with 1 n activated carbon promoted shoot elongation and inhibited the number of shoots differentiated, but was grown as abnormal shoot. Addition of 1% activated carbon and 0.5mg/l BA to culture media was effective for shoot elongation and reduction of multiple shoot and for formation of round leaves as normal leaves. Though these shoots were inoculated on the rooting medium, they could not from roots but formed multiple shoots. Boric acid, myo-inositol and sucrose were also ineffective on the rooting of teratoma shoots.

• Environmental and Resource Economics Review
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• v.25 no.2
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• pp.299-320
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• 2016

This study estimates an energy efficiency of 16 metropolitans and provinces in Korea, and measures potential energy-saving and carbon emission reduction using a non-radial data envelopment analysis method. Based on energy mix scenarios, this study also evaluates the impact of changes in energy structural adjustment on a regional environmental performance. The empirical results show that, on average, 12.70% of energy consumption and 13.73% of carbon emission can be reduced by improvement in energy efficiency, and low efficiency of oil usage in metropolitan cities is a major source of the inefficiency. Furthermore, it is found that energy mix policy should be considered to achieve an extra energy-saving and carbon reduction.

• Carbon letters
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• v.8 no.2
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• pp.120-126
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• 2007

The effect of cobalt precursor on the structure of Co supported multi-walled carbon nanotubes (MWCNTs) were studied by using X-ray photoelectron spectroscopy (XPS). MWCNTs were treated with a mixture of nitric and sulfuric acids and decorated with cobalt and/or cobalt oxides via aqueous impregnation solutions of cobalt nitrate or cobalt acetate followed by reduction in hydrogen. XPS was mainly used to investigate the phase of cobalt on MWCNTs after reduction with $H_2$ flow at $400^{\circ}C$ for 2 h. Higher cobalt-nanoparticle dispersion was found in the MWCNTS prepared via cobalt nitrate decomposition. A typical XPS spectrum of Co 2p showed the peaks at binding energy (BE) values equal to 781 and 797 eV, respectively. It is found that cobalt nitrate supported MWCNTs is more dispersive and have catalytic activity than that of cobalt acetate supported MWCNTs at same preparation condition such as concentration of precursor solution and reduction environment.

• Resources Recycling
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• v.25 no.4
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• pp.54-59
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• 2016

EAF processed slag which contains about 20 ~ 35 weight percent FetO is poured to slag pot and cooled. If we recover Fe from molten slag by the reduction, we will improve steel yield rate and reduce slag quantity poured from the furnace. Usually, carbon is used as a reductant and slag foaming agent in the EAF process. In this experiment, after melt the metal in induction furnace and then add slag with carbon and Al dross powder as a reductant, we investigated the reduction of FetO from slag and change of Phophorus content. As the result, when we use Al dross as a reductant, recovery rate is two times more than carbon. Phosphorus pick up is less than 50ppm with reduction of EAF slag.

• Applied Chemistry for Engineering
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• v.9 no.4
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• pp.475-480
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• 1998

A study on the electrochemical reduction of uranium (VI) to uranium (IV) was carried out in the mixed phases of an organic phase with uranium (VI) and aqueous phase of nitric acid by use of a highly packed glassy carbon (GC) fiber column electrode system, and a model for in-situ electrolytic stripping of uranium (VI) was suggested. The electrochemical reduction of uranium (VI) occurred faster in organic phase than in aqueous phase of the mixed phases. The uranium stripping yield increased and then became constant with the increase of organic flow rate of the electrolytic system due to the increase of diffusion resistance of uranium ions in the organic phase into the aqueous phase. Aqueous flow rate, on the other hand, didn't affect the total uranium (VI) reduction current in the system. The system combined with electrochemical reduction was confirmed to be much more effective than the simple system without it in stripping uranium.

• Korean Chemical Engineering Research
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• v.40 no.6
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• pp.664-668
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• 2002

In this work, the catalytic reduction mechanisms of NO over ACFs/copper prepared by electrolytic copper plating has been studied. It was found that copper content on carbon surfaces increased with increasing the plating time. However, a slightly gradual decrease of adsorption properties, such as, BET specific surface area, was observed in increasing the plating times within the range of well-developed micropore structures. As experimental results, nitric oxide was converted into the nitrogen and oxygen on ACFs and ACFs/copper catalyst surfaces at $500^{\circ}C$. Especially, the surfaces of ACFs/copper catalyst were found to scavenge the oxygen released by catalytic reduction of NO, which could be explained by the presence of another nitric oxide reduction mechanism between ACFs and ACFs/copper catalysts.

• Resources Recycling
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• v.13 no.5
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• pp.17-22
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• 2004

It has been carried our for establishing the methodology to upgrade $TiO_2$ by carbothermal reduction of iron oxide in ilmenite. Based on present experimental results, the possibility for substitution with rutile has been investigated. It could by proposed that the 2 wt.% $FeCl_3$ of sample and carbon of 2 equivalents are optimum conditions as a feeding materials. And also appropriate reducing temperature and reduction time were about $1100^{\circ}C$ and 30 minutes. The product obtained by the processes of carbon reduction and magnetic separation may be used the substitute mineral of rutile.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2023.11a
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• pp.199-200
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• 2023

Eco-friendly concrete contains only 5% of cement yet achieves equal or greater strength compared to conventional concrete, reducing salt-attack impact and hydration heat by more than 30% and ensuring higher construction quality for underground structures. Furthermore, eco-friendly concrete can reduce up to 90% of carbon dioxide emissions compared to traditional concrete, enabling a reduction of approximately 6,000 tons of carbon emissions for 1,000 of apartment units construction. This is equivalent to planting around 42,000 trees

• Korean Journal of Soil Science and Fertilizer
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• v.47 no.5
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• pp.374-380
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• 2014

To estimate greenhouse gas (GHG) emission, the inventory of rice cultivation at the farming without agricultural chemicals was established from farmers in Gunsan, Jeonbuk province in 2011~2012. The objectives of this study were to calculate carbon footprint and analyse the major factor of GHGs. To do this, we carried out a sensitivity analysis using the analyzed main factors of GHGs and estimated the mitigation potential of GHGs. Also we suggested agricultural methods to reduce GHGs that can be appled by farmers at this region. At the farming system without agricultural chemicals, carbon footprint of rice production unit of 1 kg was 2.15 kg $CO_2.-eq.kg^{-1}$. Although the amount of carbon dioxide ($CO_2$) emission was the largest among GHGs, methane ($CH_4$) emission had the highest contribution to carbon footprint on rice production system when it was converted to carbon dioxide equivalent ($CO_2-eq.$) multiplied by the global warming potential (GWP). Main source of $CO_2$ emission in the rice farming system without agricultural chemicals was combustion of fossil fuels used by agricultural machinery. Most of the $CH_4$ was emitted during rice cultivation practice and its major emission factor was flooded paddy field in anaerobic condition. Also, most of the $N_2O$ was emitted from rice cultivation process. Major sources of the $N_2O$ emission was application of fertilizer such as compound fertilizer. As a result of sensitivity analysis in energy consumption, diesel had the highest sensitivity among the energy inputs. With the reduction of diesel consumption by 10%, it was estimated that $CO_2$ potential reduction was about 2.0%. With reducing application rate of compound fertilizer by 10%, the potential reduction was calculated that $CO_2$ and $N_2O$ could be reduced by 0.5% and 0.9%, respectively. At the condition of 10% reduction of silicate and compost, $CO_2$ and $CH_4$ could be reduced by 1.5% and 1.6%, respectively. With 8 days more drainage than the ordinary practice, $CH_4$ emission could be reduced by about 4.5%. Drainage and diesel consumption were the main sources having the largest effect on the GHG reduction at the farming system without agricultural chemicals. Based on the above results, we suggest that no-tillage and midsummer drainage could be a method to decrease GHG emissions from rice production system.