• Journal of Korean Society for Atmospheric Environment
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• v.21 no.6
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• pp.657-666
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• 2005

The objectives of this study were to investigate atmospheric dry deposition of inorganic nitrogen-containing compounds to waterbody. Target waterbody is Juam reservoir functioning as one of the major water supply sources in Chollanamdo. Nitrate and ammonium dry deposition fluxes were directly measured using dry deposition plate (DDP) covered with greased strips and a water surface sampler (WSS). The daytime average $NO_{3}^{-}\;and\;NH_{4}^{+}$ fluxes measured with DDP and WSS were $1.7\∼2.6$ times higher than those at nighttime. The seasonal average flux of $NH_{4}^{+}$ showed the highest value in summer. The daytime and nighttime average dry deposition fluxes of particulate phase Nitogen-containing Compounds ($1.13,\;0.80\;mg/m^{2}$ day) were much higher than those of gas phase compounds ($0.50,\;0.24\;mg/m^{2}$ day).

• Journal of Korean Society for Atmospheric Environment
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• v.23 no.2
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• pp.242-249
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• 2007

Deposition fluxes of polycyclic aromatic hydrocarbons (PAHs) were measured at the Chonbuk National University located in Jeonju between June and November 2002. Fluxes of gaseous and particulate PAHs were separately obtained using a water surface sampler (WSS) and a dry deposition plate (DDP). Most of PAHs were deposited in the gaseous form since the low molecular weight PAHs dominates in the atmosphere. The deposition velocity of particulate PAHs was higher than that of gaseous PAHs when the molecular weight was low, but substantially decreased as the fine particle fraction increased with molecular weight. The deposition velocity was generally higher at high wind speeds. However, increase in the deposition velocity in unstable atmospheric conditions was also observed for gaseous PAHs of intermediate molecular weight.

• Journal of the Korean institute of surface engineering
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• v.48 no.3
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• pp.126-130
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• 2015

A high-pressure depletion method using plasma chemical vapor deposition (CVD) is often used to deposit hydrogenated microcrystalline silicon (${\mu}c-Si:H$) films of a low defect density at a high deposition rate. To understand proper deposition conditions of ${\mu}c-Si:H$ films for a high-pressure depletion method, Si films were deposited in a combinatorial way using a multi-hollow discharge plasma CVD method. In this paper the substrate temperature dependence of ${\mu}c-Si:H$ film properties are demonstrated. The higher substrate temperature brings about the higher deposition rate, and the process window of device quality ${\mu}c-Si:H$ films becomes wider until $200^{\circ}C$. This is attributed to competitive reactions between Si etching by H atoms and Si deposition.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2001.06a
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• pp.72-72
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• 2001

Plasma polymerized thin films have been deposited on Si(lOO) substrates at $25-400^{\circ}C$ using thiophene ($C_4H_4S$) precursor by plasma assisted chemical vapor deposition (PACVD) method for low-dielectric device application. In order to compare physical properties of the as-grown thin films, the effects of the plasma power, gas flow ratio and deposition temperature on the dielectric constant and thermal stability were mainly studied. XRD and TED studies revealed that the as-grown thin films have highly oriented amorphous polymer structure. XPS data showed that the polymerized thin films that grown under different RF power and deposition temperature as well as different gas ratio of $Ar:H_2$ have different stoichiometric ratio of C and S compared with that of monomer, indicating a formation of mixture polymers. Moreover, we also realized that oxygen free and thermally stable polymer thin films could be grown at even $400^{\circ}C$. The results of SEM, AFM and TEM showed that the polymer films with smooth surface and sharp interface could be grown under various deposition conditions. From the electrical property measurements such as I-V and C-V characteristics, the minimum dielectric constant and the best leakage current were obtained to be about 3.22 and $10-11{\;}A/\textrm{cm}^2$, respectively.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2007.11a
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• pp.16-16
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• 2007

• Applied Biological Chemistry
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• v.44 no.1
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• pp.7-11
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• 2001

The distribution of procymidone in a small vinyl house containing cucumber plants or mimic plants was investigated after application of smoke generator. The deposition of procymidone on glass plate and filter paper was significantly similar to that on cucumber leaves, so that glass plate and filter paper could be substituted for cucumber leaves on deposition studies. The deposition of procymidone was proportional to the horizontally projected area of surface; the deposition on the horizontal surface was maximal, and the deposition was minimal for the perpendicular surface. The amount of deposition on the backside of leaf was less than 5% compared to that on the horizontal surface of leaf. The height of leaf from the floor was not a significant factor influencing on the deposition of procymidone whether leaves were overlapped or not. However, the deposition of procymidone on the overlapped leaves was relatively less than that on the unoverlapped leaves. And the deposition difference depending on the distance between leaves was not observable. Overall, the deposition of procymidone was proportionally increased with the application rate of smoke generator, but the deposition was inversely related to the sum of the total horizontal leaf area of mimic plants and the surface area of floor.

• Korean Journal of Metals and Materials
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• v.48 no.6
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• pp.575-580
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• 2010

Effects of the surface modification on the deposition behaviors of apatite crystals in Zr-1Nb plates were studied. Zr-1Nb alloy plates were polished with abrasive papers to have different roughness and some of them were treated in NaOH or coated with collagen before deposition of apatites in the simulated body fluid (SBF). The weight gain due to the deposition of apatite crystals increased as the surface roughness increased in Zr-1Nb. The size of granular apatite crystals were found to be smaller in Zr-1Nb roughened by $162{\mu}m$ abrasive paper than in Zr-1Nb roughened by $8.4{\mu}m$ paper, suggesting the nucleation rate increased with increase of surface roughness. After, 10 days immersion in a SBF, NaOH-treated Zr-1Nb was completely coated with apatite with the deposited apatite weight comparable to that in Ti-6Al-4V. The deposition rate of Zr-1Nb was not appreciably influenced by NaOH treatment unlike the significant influence of NaOHtreatment on the deposition rate of apatite in Ti-6Al-4V. One significant observation in this study is an appreciable increase of the apatite deposition rate after collagen coating both on Zr-1Nb and Ti-6Al-4V plate, which may be caused by the interaction between collagen and $Ca^{+2}$ ions.

• Journal of the Korean Society for Heat Treatment
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• v.34 no.5
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• pp.239-244
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• 2021

Following Silicon Carbide, single crystal diamond continues to attract attention as a next-generation semiconductor substrate material. In addition to excellent physical properties, large area and productivity are very important for semiconductor substrate materials. Research on the increase in area and productivity of single crystal diamonds has been carried out using various devices such as HPHT (High Pressure High Temperature) and MPECVD (Microwave Plasma Enhanced Chemical Vapor Deposition). We hit the limits of growth rate and internal defects. However, HFCVD (Hot Filament Chemical Vapor Deposition) can be replaced due to the previous problem. In this study, HFCVD confirmed the distance between the substrate and the filament, the accompanying growth rate, the surface shape, and the Raman shift of the substrate after vapor deposition according to the vapor deposition temperature change. As a result, it was confirmed that the difference in the growth rate of the single crystal substrate due to the change in the vapor deposition temperature was gained up to 5 times, and that as the vapor deposition temperature increased, a large amount of polycrystalline diamond tended to be generated on the surface.

• 한국신재생에너지학회:학술대회논문집
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• 2010.11a
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• pp.46.1-46.1
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• 2010

Surface passivation of crystalline silicon(c-Si) surface with a-Si:H thin films has been investigated by using quasi-steady-state photo conductance(QSSPC) measurements. Analyzing the influence of a-Si:H film thickness, process gas ratio, deposition temperature and post annealing temperature on the passivation properties of c-Si, we optimized the passivation conditions at the substrate temperature of $200-250^{\circ}C$. Best surface passivation has been obtained by post-deposition annealing of a-Si:H film layer. Post annealing around the deposition temperature was sufficient to improve the surface passivation for silicon substrates. We obtained effective carrier lifetimes above 5.5 ms on average.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.29A no.4
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• pp.49-57
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• 1992

Tungsten film was deposited on the TiN surface in a low pressure chemical vapor deposition reactor and chemical reaction mechanism between TiN surface and ($WF_{6}\;and\;SiH_{4}$ was studied. Interaction of ($WF_{6}\;or\;SiH_{4}$ with TiN surface and tungsten was deposited more easily. $WF_6$ reacted with TiN activated the TiN surface to form volatile TiF_4$ and tungsten nuclei were formed. ($SiH_{4}$ was dissociated on the TiN surface to form silicon nuclei. From RBS and AES analysis, we could not detect the impurities(such as Si or TiF$_x$)at the interface between tungsten and TiN. The adhesion at the W/TiN interface became poor when the deposition temperature was below 275$^{\circ}C$.