• 한국산학기술학회논문지
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• 제14권12호
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• pp.6106-6113
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• 2013

가솔린 엔진 차량용 삼원촉매담체는 주로 코제라이트 세라믹으로 제작되는 다공성 부품으로 엔진의 혼합기가 농후한 경우 삼원촉매의 열적 내구성이 급격히 떨어져 설계 내구 수명을 제대로 만족시키지 못하고 있다. 따라서 본 연구에서는 SiC 세라믹 촉매 담체의 내구성 평가에 사용할 기계적 물성치를 유한요소해석으로 구하기 위하여 등가물성평가방법을 이용하여 SiC 세라믹 하니컴 담체의 기계적 물성치를 유한요소해석용 시험편으로 구하였다. MOR과 탄성계수는 코제라이트 세라믹 하니컴 담체에 비하여 SiC 세라믹 하니컴 담체가 최소 2배와 9.3배 정도 크게 평가되고 있어 SiC 세라믹 하니컴 담체는 코제라이트 세라믹 하니컴 담체에 비하여 높은 구조 강도를 가지고 있다.

• Asian Journal of Atmospheric Environment
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• 제2권2호
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• pp.75-80
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• 2008

A new-type apparatus decomposing volatile organic compounds (VOCs) using a combination system of an electrical exothermic SiC honeycomb and a catalytic filter was developed. This linear combination system is very useful to the catalytic decomposition of VOCs, because the gas involving VOCs is well heated in the SiC honeycomb and then flows into the catalytic filter. In the proposed apparatus, the outlet gas temperatures of SiC honeycomb maintained at ca. $300^{\circ}C$ after 5 min from the starting of applying electric current, and sufficient for the catalytic degradation of VOC components, i.e. toluene, isopropanol, methyl ethyl ketone and ethyl acetate. The average decomposition rate of total VOCs exhausted from a printing factory was 85% using pt catalyst at SV=19,000 in this system.

• 한국태양에너지학회:학술대회논문집
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• 한국태양에너지학회 2012년도 춘계학술발표대회 논문집
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• pp.120-125
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• 2012

Daegu Solar Power Tower Plant of a 200 kW thermal capacity uses an open air receiver. An air receiver is generally based on the volumetric receiver concept with porous ceramic absorbers. Because absorber material is important in the volumetric receiver, ceramic materials with excellent thermal conductivity, high solar absorptivity and good thermal stability have been researched. KIER also developed SiC honeycomb absorber modules and evaluated performance of the modules at the KIER solar furnace. For performance evaluation, we made an open volumetric receiver containing the modules and measured the outlet temperature and the efficiency. It is demonstrated that performance of the KIER absorber is comparable to that of a reference absorber developed by DLR.

• 한국재료학회지
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• 제25권9호
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• pp.450-454
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• 2015

A simulation method to estimate microstructure dependent material properties and their influence on performance for a honeycomb structured SiC heating element has been established. Electrical and thermal conductivities of a porous SiC sample were calculated by solving a current continuity equation. Then, the results were used as input parameters for a finite element analysis package to predict temperature distribution when the heating element was subjected to a DC bias. Based on the simulation results, a direction of material development for better heating efficiency was found. In addition, a modified metal electrode scheme to decelerate corrosion kinetics was proposed, by which the durability of the water heating system was greatly improved.

• 한국대기환경학회지
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• 제23권1호
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• pp.84-96
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• 2007

We performed the experiments to manufacture the hydrophobic $200cells/in^2$-zeolite honeycomb using HY-type zeolite of Si/Al ratio of 80 for separating and removing the VOCs emitted from small and medium size-plants by adsorption and to determine the drying method for the honeycomb at $105^{\circ}C$ without cracking, then measured performances of the honeycomb to adsorb the benzene, o-xylene, and MEK and to desorb the benzene and MEK saturated on the honeycomb by the nitrogen gas as the desorption gas. As a results, the good honeycomb was formed and the honeycomb was not cracked when the mixing ratio of the zeolite to bentonite to methyl cellulose to polyvinyl alcohol to glycerine to water is 100 : 8.73 : 2.18 : 4.19 : 1.38 : 126 and dried the honeycomb at $105^{\circ}C$ for 24 hours in the drying oven. The shape of the dried honeycomb was not changed after calcination, and the compressive strengths of the honeycomb after drying and calcination were 6.7 and $0.69kg/cm^2$, respectively. The adsorption efficiencies of the honeycomb for benzene, o-xylene, and MEK were $92{\sim}96%$ at the room temperature. The desorption efficiency at $180^{\circ}C$ was higher than that at $150^{\circ}C\;by\;1.5{\sim}13.8%$ depending on the flow rate of the nitrogen gas, and it was found that desorption efficiency is higher than 85% at $180^{\circ}C$ and 1.0L/min of the nitrogen gas. At $180^{\circ}C$ and 0.2 L/min, the concentration of the benzene and MEK in the used desorption gas are higher than 40,000 and 50,000ppm, respectively, so it be used as the fuel for preheating the desorption gas fed into the column in desorption cycle.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2012년도 제42회 동계 정기 학술대회 초록집
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• pp.128-128
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• 2012

We investigated the atomic and electronic properties of graphene grown by Pd silicidation and intercalation using LEED, STM, and ARPES. Pd was deposited on the 6H-SiC(0001) surface at RT. The formation of Pd silicide gives rise to breaking of Si-C bonds of the SiC crystal, which enables to release C atoms at low temperature. The C atoms are transformed into graphene from $860^{\circ}C$ according to the LEED patterns as a function of annealing temperature. Even though the graphene spots were observed in the LEED pattern and the Fourier transformed STM images after annealing at $870^{\circ}C$, the topography images showed various superstructures so that graphene is covered with Pd silicide residue. After annealing at $950^{\circ}C$, monolayer graphene was revealed at the surface. The growth of graphene is not limited by surface obstacles such as steps and defects. In addition, we observed that six protrusions consisting of the honeycomb network of graphene has same intensity meaning non-broken AB-symmetry of graphene. The ARPES results in the vicinity of K point showed the non-doped linear ${\pi}$ band structure indicating monolayer graphene decoupled from the SiC substrate electronically. Note that the charge neutrality of graphene grown by Pd silicidation and intercalation was sustained regardless of annealing temperature in contrast with quasi-free- standing graphene induced by H and Au intercalation. Further annealing above $1,000^{\circ}C$ accelerates sublimation of the Pd silicide layer underneath graphene. This results in appearance of the $(6r3x6r3)R30^{\circ}$ structure and dissolution of the ${\pi}$ bands for quasi-free-standing graphene.

• Advances in nano research
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• 제12권2호
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• pp.213-221
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• 2022

Silicon carbide (SiC) is a binary carbon-silicon compound. In its two-dimensional form, monolayer SiC is composed of a monolayer carbon and silicon atoms constructed as a honeycomb lattice. SiC has recently been receiving increasing attention from researchers owing to its intriguing electronic properties. In this present work, SiC nanoribbons (SiCNRs) are modelled and simulated to obtain accurate electronic properties, which can further guide fabrication processes, through bandgap engineering. The primary objective of this work is to obtain the electronic properties of monolayer SiCNRs by applying numerical computation methods using nearest-neighbour tight-binding models. Hamiltonian operator discretization and approximation of plane wave are assumed for the models and simulation by applying the basis function. The computed electronic properties include the band structures and density of states of monolayer SiCNRs of varying width. Furthermore, the properties are compared with those of graphene nanoribbons. The bandgap of ASiCNR as a function of width are also benchmarked with published DFT-GW and DFT-GGA data. Our nearest neighbour tight-binding (NNTB) model predicted data closer to the calculations based on the standard DFT-GGA and underestimated the bandgap values projected from DFT-GW, which takes in account the exchange-correlation energy of many-body effects.

• 한국세라믹학회지
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• 제45권2호
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• pp.132-137
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• 2008

The main purpose of this study is enhancing the filtering efficiency, performance and durability of filter by growing SiC whiskers on cordierite honeycomb substrate. The experiment was performed by Chemical Vapor Infiltration (CVI) in order to control pore morphology of substrate. Increasing the mechanical strength of porous substrate is one of important issues. The formation of "networking structure" in the pore of porous substrate increased mechanical strength. The high pressure gas injection to the specimen showed that a little of whiskers were separated from substrate but additional film coating enhanced the stability of whisker at high pressure gas injection. Particle trap test was performed. More nano-particle was trapped by whisker growth at the pore of substrate. Therefore it is expected that the porous cordierite which deposited the SiC whisker will be the promising material for the application as filter trapping the nano-particles.

• 한국대기환경학회지
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• 제12권2호
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• pp.121-130
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• 1996

The catalysts composed of Pt, Pd and W as active-components, $Al_{2}O_{3}$ and $SiO_{2}$ as supports, were perpared on the honeycomb type substrate and characterized by BET, SEM, TGA, FT-IR and XRD for diesel emission control. CO, $C_{3}H_{6}$, and $SO_{2}$ oxidation was carried out over these catalysts in a fixed bed continuous flow reactor at the temperatures between 100-500.deg.C and reactant gas was composed of 10 vol.% $O_{2}$, 1 vol.% CO, 0.8 vol.% $C_{3}H_{6}$ and 88.2 vol.% $N_{2}$. It was found that under these experimental conditions, the CO, $C_{3}H_{6}$ oxidation activity of Pt-W catalyst was higher than that of any other prepared catalyst, and this catalyst had also a good inhibition effect on $SO_{2}$ oxidation. Also it was show that the influence of $SO_{2}$ on $Al_{2}O_{3}$ was more sever than that of $SO_{2}$ on $SiO_{2}$.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2015년도 제49회 하계 정기학술대회 초록집
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• pp.109.2-109.2
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• 2015

Graphene, as a single layer of $sp^2$-bonded carbon atoms packed into a 2D honeycomb crystal lattice, has attracted much attention due to its outstanding properties such as high carrier mobility, chemical stability, and optical transparency. In order to synthesize high quality graphene, transition metals, such as nickel and copper, have been widely employed as catalysts, which need transfer to desired substrates for various applications. However, the transfer steps inevitably induce defects, impurities, wrinkles, and cracks of graphene. Here, we report a facile transfer-free graphene synthesis method through nickel and carbon co-deposited layer, which does not require separately deposited catalytic nickel and carbon source layers. The 100 nm NiC layer was deposited on the top of $SiO_2/Si$ substrates by nickel and carbon co-deposition. When the sample was annealed at $1000^{\circ}C$, the carbon atoms diffused through the NiC layer and deposited on both sides of the layer to form graphene upon cooling. The remained NiC layer was removed by using nickel etchant, and graphene was then directly obtained on $SiO_2/Si$ without any transfer process. Raman spectroscopy was carried out to confirm the quality of resulted graphene layer. Raman spectra revealed that the resulted graphene was at high quality with low degree of $sp^3$-type structural defects. Furthermore, the Raman analysis results also demonstrated that gas flow ratio (Ar : $CH_4$) during the NiC deposition and annealing temperature significantly influence not only the number of graphene layers but also structural defects. This facile non-transfer process would consequently facilitate the future graphene research and industrial applications.