• Economic and Environmental Geology
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• v.53 no.6
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• pp.793-807
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• 2020

The policy for Green New Deal will promote the shift of the application to coal as feedstock from coal as fuel. Coal can be used as fuel for production of hydrogen and as feedstock materials such as synthetic graphite or activated carbon. Hydrogen is obtained from syngas produced through Steam carbon(SC), Water-Gas Shift(WGS), and Carbonation reactions, and these processes should be used in conjunction with CO2 sequestration technology. Anthracite has a potential in terms of cost advantage as a feedstock compared to a petroleum pitch, because Synthetic graphite is prepared by heat treating an anthracite with high rank to a graphitization temperature which is in the range of 2400~2800℃, in the presence of inorganic catalyst such as silicon or iron. From several studies, it has been confirmed that coal-based activated carbon(AC) is manufactured with quality similar to the large specific surface area and much micropore volume of lignin-based AC, can be prepared. Therefore it is expected that lignin-based AC is replaced to coal-based AC.

• Journal of the Korean Society of Propulsion Engineers
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• v.18 no.4
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• pp.67-73
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• 2014

The dry sliding wear behavior of graphite that is used as the sealing material to cut off hot gas was evaluated as a function of applied load, sliding speed and temperature. The reciprocating wear tests were carried out at room temperature and elevated temperatures. An attempt has been made to develop a mathematical model by response surface methodology and an analysis of variance technique was applied to confirm the validity of the developed model. Also, the wear mechanism was compared through the observation of the worn surface by SEM analysis.

• Proceedings of the Korean Nuclear Society Conference
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• 1996.05c
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• pp.39-45
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• 1996

핵비확산 목적으로 원심분무방법으로 저농축 우라늄 고밀도의 U$_3$Si$_2$구형분말 분산핵연료를 개발하는 일환으로 융점이 높은 U$_3$Si$_2$원심분무용 도가니와 nozzle에 적합한 재료를 선정하고자 zirconia계 물질과 yttria물질에 대한 양립성을 시험하였다. ZrO$_2$계 세라믹은 U$_3$Si$_2$와 우수한 양립성을 나타냈는데 부분 안정화시킨 Zirconia가 Crack 발생이 없어 완전 안정화시킨 것보다 내열충격이 더 양호한 것으로 보인다. Zirconia 도가니는 흑연과 반응하여 표면에 carbide를 형성하여 박리 되는 현상이 발생되었는데 부분 안정화 zirconia가 약간 더 많이 형성됨을 나타냈다. Yttria는 180$0^{\circ}C$이상에서 흑연과 반응하여 액상으로 형성되고 U$_3$Si$_2$와도 반응하여 사용에 부적합한 것으로 판명되었다. 내열충격이 비교적 우수한 부분 안정화 zirconia로 tundish를 제조하여 U$_3$Si$_2$를 원심분무한 결과 nozzle확장되지 않아서 입도분포가 협소한 분말을 얻는데 성공하였다.

• Applied Chemistry for Engineering
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• v.3 no.4
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• pp.657-662
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• 1992

For describing the bipolar packed-bed electrode cell filled with graphite pellete electrode, the application of the model of equivalent circuit was studied. The ratio between the Faradaic current through bipolar electrodes and the applied current was dependent on the resistance coefficient, specific conductivity of electrolyte, and electrolyte circulation rate. The ratio of the Faradaic current through bipolar electrodes to the applied current increased with the applied current(or cell voltage), but decreased with the increase of electrolytic conductivity and circulation rate of the electrolyte.

• Proceedings of the KAIS Fall Conference
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• 2011.05a
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• pp.155-157
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• 2011

본 논문에서는 In-situ 전기화학 AFM과 In-situ 전기화학 Raman을 주된 분석방법으로 리튬 이차전지의 흑연 음극과 PC계 전해질 계면에서의 반응을 이해하고자 하였다. In-situ 전기화학 AFM 분석방법을 통하여 PC계 전해질에서 용매화된 리튬의 삽입/탈리반응이 진행되는 것을 확인할 수 있었으며 In-situ 전기화학 Raman 분석방법을 이용하여 PC계 전해질에서는 삼원계 Li-GIC가 생성되는 것을 확인할 수 있었다.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.18 no.1
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• pp.83-90
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• 2020

The Graphite Isotope Ratio Method (GIRM) can verify non-proliferation of nuclear weapon by estimating the total plutonium production in a graphite-moderated reactor. Using the reactor, plutonium is generated and accumulated through the ²³⁸U neutron capture reaction, and impurities in the graphite are converted to nuclides due to the nuclear reaction. Therefore, the amount of plutonium production and concentration of the impurities are correlated. However, the plutonium production cannot be predicted using only the absolute concentration of the impurities. It can only be predicted when the initial concentration of the impurities is obtained because the concentration, at a certain time, depends on it. Nevertheless, the ratios of the isotopes in an element are known regardless of the impurity of an element in the graphite moderator. Thus, the correlation between the isotope ratio and amount of plutonium produced helps predict plutonium production in a graphite-moderated reactor. Boron, Lithium, Chlorine, Titanium, and Uranium are known as indicator elements in the GIRM. To assess whether the correlation between the indicator isotope and amount of plutonium produced is independent of the initial concentration of the impurities, four different impurity compositions of graphite were used. ¹⁰B/¹¹B, ³⁶Cl/³⁵Cl, ⁴⁸Ti/⁴⁹Ti, and ²³⁵U/²³⁸U had a consistent correlation with the cumulative plutonium production, regardless of the initial impurity concentration of the graphite, because these isotopes were not generated through the nuclear reaction of other elements. On the other hand, the correlation between ⁶Li/⁷Li and plutonium production depended on the initial concentration of the impurities in graphite. Although ⁷Li can be produced through the neutron capture reaction of ⁶Li, the (n, α) reaction of ¹⁰B was the major source of ⁷Li. Therefore, the initial concentration of ¹⁰B affected the production of ⁷Li, making Li unsuitable as an indicator element for the GIRM.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 1999.10a
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• pp.41-42
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• 1999

• Proceedings of the KAIS Fall Conference
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• 2007.11a
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• pp.356-358
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• 2007

본 논문에서는 농도가 다른 EC계의 전해질 용액 중에서 흑연의 Cyclic voltammetry(CV)를 측정하였다. CV후 전극표면에 생성된 SEI를 투과형 전자현미경으로 분석한 결과, PC계에서 얻어지는 결과와 유사하게 충 방전 반응 및 생성된 SEI의 성질이 전해질의 농도에 크게 의존하고 있음을 확인하였다.

• Korean Journal of Materials Research
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• v.3 no.3
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• pp.300-309
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• 1993

Abstract In this work. gasification of graphite cores from nickel-coated graphite composite powders was carried out to munufacture the hollow nickel metal powders which can be used as a raw materials for porous nickel metal strips. Graphite cores were gasified by $H_2O-H_2$ mixture gases at the temperature between $800^{\circ}C$ and $900^{\circ}C$ and nearly all removed from the composite powders within 1 hour. The hollow nickel metal powders prepared from 82.2wt. % Ni-17.8wt. % C composite powders which have the graphite cores of 21${\mu}$m average size were pressed and sintered at $1150^{\circ}C$ for 1 hour in vacuum furnace. The porosities of green and sintered compacts were 45% and 30%. respectively, and pores were distributed very homogeneously in the sintered compact. It was confirmed that pore distribution and porosity in porous materials can be easily controlled by using hollow powders as a raw materials.

• Journal of the Korean Ceramic Society
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• v.40 no.12
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• pp.1177-1182
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• 2003

The porous sensing materials for BaTiO$_3$ gas sensors were fabricated by adding the graphite powders. The crystalline structure and microstructure of the porous BaTiO$_3$-based ceramics were studied. All the sintered bodies showed a tetragonal perovskite structure. The porosity increased with increasing graphite contents. This is mainly due to an enhanced evolution of CO and $CO_2$ gases resulting from the exothermic reactions of graphite and oxygen during the sintering. It was found that the discrepancy in the resistivities measured in air and CO atmospheres at high temperatures (>∼20$0^{\circ}C$) became remarkable with increasing temperature. The sensitivity of CO gas increased with porosity, since the reactions between CO gas and $O_2$$^{[-10]}$ and between CO gas and $O^{[-10]}$ are active due to the formation of many reaction sites. The porous BaTiO$_3$-based ceramics could be promising as a sensing material for CO gas sensors.