• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1996년도 춘계학술대회 논문집
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• pp.166-169
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• 1996

It is well known that the metallo-phthalocyanines (MPcs) are sensitive to toxic gaseous molecules such as NO$_2$ and also chemically and thermally stable and it is recently reported that SnO$_2$ thin films have a selective sensitivity to NO$_2$ and SO$_2$ gas. Therefore, it is interesting to prepare phthalo-cyanine Langmuir-Boldgett(LB) films containing tin as a chemical sensor for NO$_2$ and SO$_2$ gas and test the selectivity with these tin containing LB films. First, in this study, ultra thin films of Octa (2-ethylhexyloxy) tin-phthalocyanine were prepared on various substrates by LB method. $\pi$-A isotherm and transfer characteristics of these films were investigated. The formation of these films was determined by ellipsometry. Intrinsic current-voltage(I-V) characteristics of these films were also measured.

• 한국표면공학회:학술대회논문집
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• 한국표면공학회 2009년도 춘계학술대회 논문집
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• pp.177-181
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• 2009

Compositional gradient CrNx coatings were fabricated using arc ion plating in Ar/$N_2$ gaseous mixture by gradually increasing $N_2$ flux rate from 0 to 120 SCCM. The effect of negative substrate bias on the film microstructure and mechanical properties were systematically investigated with XRD, GDOES, and SEM. The results show that substrate bias has an important influence on film growth and microstructure of gradient CrNx coatings. The coatings mainly crystallized in the mixture of hexagonal $Cr_{2}N$ and fcc CrN phases. By increasing substrate bias, film microstructure evolved from an apparent columnar structure to an equiaxed one. With increasing substrate bias, deposition rate first increased, and then decreased. The maximum of deposition rate was 15 nm/min obtained at a bias of -50V.

• 한국분말재료학회지
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• 제1권1호
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• pp.27-34
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• 1994

Commercial pure iron powder and iron powder of coated 0.45% phosphorus were mixed with graphite powder in dry mixer to control carbon content from 0 wt% to 0.8 wt%. Mixed powder was pressed in the mould under the pressure of 510 MPa. Compacts were sintered at 118$0^{\circ}C$ for 40 min. in cracked ammonia gaseous atmosphere. Some of these sintered specimens were quenched in oil, and tempered in Ar gas. All of these specimens were investigated for microstructure, density and hardness in relation to coated phosphorus and carbon content. The results obtained were as follows: (1) The microstructure of the sintered speciments revealed that the amount of pearlite was increased with increasing C content but decreased by P-addition. (2) The P-addition affected the microstructure of pores in which the pore shape became round and its mean size was decreased by P-addition. (3) After tempering of sintered specimens the structure of pearlite was changed from fine structure to coarse one in P added specimen. (4) Hardness was higher in P added specimens.

• 한국연소학회:학술대회논문집
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• 한국연소학회 2012년도 제44회 KOSCO SYMPOSIUM 초록집
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• pp.93-96
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• 2012

In the industrial furnaces or reactors, entrainment of the material particles is one of the important issues from the point of view of efficient material-use. The particles of solid phase which has submicron unit are easily entrained with gas phase as a reacting agent or product, and it causes a loss of the material. In this study, wind-tunnel experiment is carried out to interpret the distribution of the particles entrained along the tunnel length. Through CFD-based computational analysis of the experiment, availability of result from the CFD analysis associated with particle size distribution and gaseous velocity to practical system is evaluated.

• 한국연소학회:학술대회논문집
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• 한국연소학회 2012년도 제44회 KOSCO SYMPOSIUM 초록집
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• pp.37-40
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• 2012

In an entrained flow coal gasifier, predicting the reaction behavior of pulverized coal particles requires detailed information on devolatilization, char gasification, gaseous reactions, turbulence and heat transfer. Among the input parameters, the rate of devolatilization and the composition of volatile species are difficult to determine by experiments due to a high pressure (~40 bar) and temperature (${\sim}1500^{\circ}C$). This study investigates the effect of devolatilization models on the reaction and heat transfer characteristics of a 300 MWe Shell coal gasifier. A simplified devolatilization model and advanced model based on Flashchain were evaluated, which had different volatiles composition and devolatilization rates. It was found that the tested models produce similar flow and reaction trends, but the simplified model slightly over-predict the temperature and wall heat flux near the coal inlets.

• 유기물자원화
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• 제4권2호
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• pp.71-75
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• 1996

Trimethylamine, dimethylamine, methylamine 등의 아민류를 분해할 수 있는 미생물을 TMA를 성장기질로 사용한 농화배양으로부터 분리하였다. 분리된 균은 Methylobacterium sp. T32에 속하는 균으로 동정되었다. 이 균은 메탄올, 메틸아민류를 분해할 수 있으나, 다탄소화합물중에서는 malate, succinate, betaine과 같이 극히 제한된 종류의 유기화합물만을 분해할 수 있는 restricted facultative methylotroph였다. 이 균을 분변토에 고정하여 biofilter를 제작하였을 때 TAM gas를 SV $30h^{-1}$, 농도 120ppm를 연속적으로 분해했다.

• Journal of Korean Society for Atmospheric Environment
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• 제21권E2호
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• pp.57-65
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• 2005

An experimental study was performed on the decomposition of gaseous ammonia and two selected volatile organic compounds (VOCs: toluene and acetone) in a combined nonthermal plasma reactor with corona and glow discharges. A lab pilot scale reactor (206 liter) equipped with a high electric power pack was used to determine the decomposition efficiency in relation with the inlet concentration and applied voltage. Three different types of discharging electrode such as wired rack, wire strings for corona discharge, and thin plate for glow discharge were put in order in the reactor. While decomposition of ammonia decreased with an increase in the initial concentration, acetone showed an opposite result. In the case of toluene however no explicit tendency was found in toluene and aceton. Negative discharge resulted in high decomposition efficiency than the positive one for all gases. A better removal of gas phase element could be achieved when fume dust were present simultaneously.

• 한국대기환경학회지
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• 제20권3호
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• pp.421-426
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• 2004

Dry deposition fluxes of inorganic acidic species to the waterbody were measured by the dry deposition sampler (DDS). DDS was composed of three pans filled with pure water. An average concentration increase during the sampling time, after removing an abnormal value if existed, was considered as the input by deposition. Important operation parameters such as the amount of water used and sampling time were determined through a series of laboratory experiments. The deposition flux measured by DDS was compared with that by the water surface sampler developed by Yi et ai. (1997a,b).

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 1996년도 경북지부 결성 및 추계학술발표회 논문집
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• pp.50-53
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• 1996

This paper reports the experimental results for the determination of the overall partition coefficient of VOCs in unsaturated soil, A chromatographic method was used for the determination of gaseous partition coefficients to natural soil under various water content conditions. The equilibrium vapor pressure of water over saturated salt solution was used to fix the relative humidity of the air and control the water content of the soil systems. The transport behavior was studied for dichloromethane, trichloroethane and dichlorobenzene pollutants, with log octanol-water partition coefficients(log $K_{ow}$ ) which range from 1.25 to 3.39, or water to soil partitioning which varies by 135 times; water solubility constants which vary by 3 times; and vapor pressures which range from 1 to 362 torr. Water content of the soil had a pronounced effect on the effective partition coefficient(between gas and soil + water stationary phase) as well as on the effective dispersion coefficient.

• 한국연초학회지
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• 제7권2호
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• pp.169-178
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• 1985

In the previous paper, the kinetics of cellulose were described. In this study, the ability of some additives to act as a flame promoter for cellulose was investigated using dynamic thermogravimetry and differential scanning calorimetry. The treated cellulose was thermally decomposed through the two model as previously noted with the untreated cellulose. The first step was associated with the flaming combustion of volatile material released in the fraunentation process and the second was caused by the glowing combustion of carbonaceous residue. The first group of the additives, which could be divided into two groups by the pyrolytic mechanism of cellulose, appeared to catalyze the fragmentation, maximizing the degradation to produce tarry products, with gaseous flammable substrate. The heat evolved in flaming combustion mode was increased significantly by the treatment of the cellulose retained 1-5% of the first group additives.