• Journal of the Korean Institute of Gas
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• v.27 no.4
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• pp.85-91
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• 2023

In this study, an experimental study was conducted on the flame behavior, combustion dynamics, and NOx emission characteristics for hydrogen co-firing with the EV burner which is the first stage combustor of GT24. It was confirmed that as the hydrogen co-firing rate increases, the NOx emission increases. This change was elucidate to be the result of a combination of changes in penetration depth due to changes in fuel density, reduction in fuel mixing due to changes in flame position due to increased flame propagation speed, and oscillation of fuel mixedness due to combustion instability. Through pressurization tests in the range of 1.3 to 3.1 bar, NOx emission characteristics under high-pressure operating conditions were predicted, and based on this, the hydrogen co-firing limits of the EV burner was evaluated.

• Korean Journal of Environment and Ecology
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• v.26 no.3
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• pp.446-453
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• 2012

This study estimated how much carbon can be sequestered if we plant trees in non-forested areas in the 36 hole Oak Valley Golf Courses in Gangwon Province, Korea. We identified plantable areas where planting trees will not affect golf game using high resolution aerial photography and ground survey and estimated the annual carbon sequestration rate of the planted trees using biomass equations. Of the golf courses, 30.3% were covered by forest. Other major land cover types include lawn, waterbody, baresoil, buildings, and roads. The plantable areas consist of $106,101m^2$ of lawn (6.0% of the study site) and $177,531m^2$ of low density forest (10.1% of the study site). We assumed to plant Mongolian oaks with 10 cm in diameter at brest height with the density of $0.3/m^2$ in the lawn and $0.2/m^2$ in the low density forest. The planting simulation shows that the total number of the newly planted trees were 67,336, and the total carbon sequestered during the subsequent year was 392.9 tC/yr, which offset 12.5% of the total carbon emitted from the golf courses. The annual carbon sequestration rate gradually increases and reaches its maximum level at 440.5 tC/yr in 15 years since the initial reforestation (14.0% of the carbon emission from the golf courses).

• Membrane Journal
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• v.12 no.2
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• pp.107-119
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• 2002

Carbon-silica ($C-SiO_2$) membranes can be easily prepared by the pyrolysis of two-phase copolymers containing an aromatic imide block and a siloxane block and remarkably high permselectivities of $He/N_2, O_2/N_2,$ and $CO_2/N_2$. The pyrolysis of the imide-siloxane block copolymers was carried out at different final temperatures, $600^{\circ}C, 800^{\circ}C,$ and $1000^{\circ}C$ under an inert atmosphere, and is the first reported case of the precursors being used for the preparation of carbon membrane. The polymeric precursors were synthesized in a wide range of siloxane content and different final morphology, and the pyrolozed membranes were tested with a high vacuum time-lag method at $25^{\circ}C$ and 76cmHg of feed pressure. In experiments with He, $CO_2, O_2 \;and \;N_2$, the membranes were found to have good $O_2/N_2$ selectivity up to 32.2 and $O_2$ permeability on the order of $10-8/cm^2(STP)cm/cm^2seccmHg.$.

• Applied Chemistry for Engineering
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• v.25 no.3
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• pp.292-299
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• 2014

In this study, nitrogen doped carbon felt (CFt) is prepared using thermal oxidation and liquid phase ammonia treatment to improve the efficiency for vanadium redox flow batteries (VRFB). The electrochemical properties of prepared CFt electrodes are investigated using cyclic voltammetry (CV) and charge/discharge test. The XPS result shows that the increase of liquid phase ammonia treatment temperature leads to the increased nitrogen functional group on the CFt surface. Redox reaction characteristics using CV reveal that the liquid phase ammonia treated CFt electrodes are more reversible than the thermally oxidized CFt. When CFt is treated by the liquid phase ammonia at $300^{\circ}C$, VRFB cell energy efficiency, voltage efficiency, and current efficiency are increased about 6.93%, 1.0%, and 4.5%, respectively, compared to those of the thermally oxidized CFt. These results are because nitrogen functional groups on CFt help to improve the electrochemical properties of redox reaction between electrode and electrolyte interface.

• Proceedings of the Membrane Society of Korea Conference
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• 1994.04a
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• pp.19-20
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• 1994

막(Membrane)을 이용한 기체분리는 막층 네에서의 기체분자의 투과성의 차이를 이용하여 기체분리를 행하는 것으로 공기중 산소의 분리 (산소부화막 이라고도 한다), 수성가스중의 수소의 농축분리, 탄화수소가스중 이산화탄소의 분리, 그 외에 산업폐가스 (황화수소, 일산화탄소, 아황산가스 등)의 분리등이 있다. 이 중 산소부화막은 의료용 산소공급장치나 산업용 용광로의 연소효율 증진에 효과적으로 이용될 수 있으며 산업폐가스이 분리공정은 환경공학적 측면에서 활용이 가능하다.

• Proceedings of the Korean Nuclear Society Conference
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• 1995.05a
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• pp.796-802
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• 1995

본 연구의 목적은 원자력 배관용 스테인레스강의 J-R곡선을 예측하기 위한 2가지 방법 올 제시하는 것이다. 첫 번째 방법에서는 균열길이/시편폭 비를 변수로 한 탄소성 유한요소해석을 수행하여 파괴변형률에 근거한 P-$\delta$곡선을 얻고, 이 결과로부터 일반궤적법을 응용하여 J-R곡선을 구하였다. 두 번째 방법에서는 $\sigma$-$\varepsilon$곡선과 J-R곡선의 상관관계를 통계처리하여 응력-변형률시험결과로부터 J-R곡선을 예측할 수 있는 실험식을 제시하였다. 본 연구에서 제시한 방법들을 이용하여 구한 예측결과는 실험결과와 대체로 잘 일치하였다.

• Transactions of the Korean Society of Mechanical Engineers
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• v.14 no.4
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• pp.866-872
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• 1990

본 연구에서는 전보의 $J_{IC}$ 시험법 기교에 이어, 전기저항 가열로(splic furnace)와 고온용 신장계(high temperatuer extensometer)를 이용하여, 고온에서의 $J_{IC}$ 측정의 가능성을 검토하였으며, 고온용 신장계를 사용할 때와 COD게이지를 사용할 때의 $J_{IC}$값의 차이를 비교 검토하였다. 또한, 20.deg. C~600.deg. C에서, 온도 변화가 $J_{IC}$값에 미치는 영향에 대하여 고찰하여 보았다.

• Proceedings of the KIEE Conference
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• summer
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• pp.602-603
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• 2004

전력용 변압기에 아크나 코로나가 발생하여 국부가열이 존재하면 절연유나 절연지가 분해하여 저분자의 탄화수소, 수소, 탄화가스, 일산화탄소 둥이 발생하여 절연유에 용해된다. 절연유에 용해된 가스를 실시간 분석하여 변압기의 이상을 조기에 발견하여 운전의 효율성을 높이고 고장을 사전에 예방하기 위한 기술이 전개되고 있다. 경제적인 측면에서 단일 수소가스 검출센서가 널리 보급되어 실용화되고 있는 실증이다. 이 논문에서는 전력용 변압기의 국부적 고온인 경우의 가열온도, 가열시간 및 방전에 대하여 수소가스 주도형 센서의 응답특성에 관하여 고찰하였다.

• Journal of the Korean Wood Science and Technology
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• v.44 no.3
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• pp.449-456
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• 2016

This study was aimed to quantify the amount of carbon dioxide emissions and to suggest suitable plans which consider the carbon emission reduction in the manufacturing process of the domestic structural glued laminated timber. Field investigation on two glued laminated timber manufacturers was conducted to find out material flow input values such as raw materials, transportation, manufacturing process, and energy consumption during manufacturing process. Based on the collected data and the relevant literatures about life cycle inventory (LCI), the amount of carbon dioxide emission per unit volume was quantified. Results show that the carbon dioxide emissions for sawing, drying and laminating process are 31.0, 109.0, 94.2 kg $CO_2eq./m^3$, respectively. These results show 13% lesser amount of total carbon dioxide emissions compared with the imported glued laminated timber in Korea. Furthermore, it was decreased about 37% when the fossil fuel would be replaced with biomass fuel in drying process. Findings from this study is effectively used as the basic data on the life cycle assessment of wooden building.

• Applied Chemistry for Engineering
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• v.33 no.6
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• pp.630-635
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• 2022

Copper(II) oxide (CuO), electroless plated on a nitrogen-containing carbon sponge prepared by a melamine sponge thermal treatment, was developed as a nitric oxide (NO) gas sensor that operates without a wafer. The CuO content on the surface of the carbon sponge increased as the plating time increased, but the content of nitrogen known to induce NO gas adsorption decreased. The untreated carbon sponge showed a maximum resistance change (5.0%) at 18 min. On the other hand, the CuO plated sample (CuO30s-CS) showed a maximum resistance change of 18.3% in 8 min. It is considered that the improvement of the NO gas sensing capability was caused by the increase in hole carriers of the carbon sponge and improved movement of electrons due to CuO. However, the NO gas detection resistance of the CuO electroless plated carbon sponge for 60 s decreased to 1.9%. It is considered that the surface of the carbon sponge was completely plated with CuO, resulting in a decrease in the NO gas adsorption capacity and resistance change. Thus, CuO-plated carbon sponge can be used as an effective NO gas sensor because it has fast and excellent resistance change properties, but CuO should not be completely plated on the surface of the carbon sponge.