• The Korean Journal of Ceramics
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• v.5 no.1
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• pp.44-49
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• 1999

In order to improve the oxidation resistance of $Ti_3Al$, Ti-25at.%Al composites containing dispersed particles of 15wt.%SiC were prepared by a tubular mixing-spark plasma sintering method. The sintered composites had $Ti_3Al$, SiC, $Ti_5Si_3$ and TiC. The presence of $Ti_5Si_3$ and TiC indicates that some of SiC particles reacted with Ti to from more stable phases. From oxidation tests at 800, 900 and $1000^{\circ}C$ under 1 atm of pure oxygen, it was found that the oxidation rate of Ti3Al was effectively reduced by the addition of SiC. The scale was primarily composed of an outer $TiO_2$ layer having some $Al_2O_3 $islands, an intermediate relatively thick $Al_2O_3 $ layer, and an inner $TiO_2+Al_2O_3+SiO_2$ mixed layer. Beneath the scale, Kirkendall voids were seen.

• International Journal of Concrete Structures and Materials
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• v.3 no.1
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• pp.15-23
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• 2009

Over about 30% of problems in construction is related to water-leaking, and the loss from this problem can incur as much as three times the cost of initial construction. Thus, water vapor pressure is known to be the primary cause of defective waterproofing. Accordingly, the theories on the relationship between water pressure and temperature as well as damp-proofing volume of concrete and the change in vapor pressure volume were reviewed and analyzed in this study by making test samples after spraying a dampness remover and applying waterproofing materials to the prepared test specimens. The result of measuring water vapor pressure with the surface temperature of the waterproofing (fluid-applied membrane) layer at the experimental temperature setting of about $10^{\circ}C$, which is the annual average temperature of Seoul, indicated that (1) the temperature of the fluid-applied membrane elevated to about $40^{\circ}C$, and the water vapor pressure generated from the fluid-applied membrane was about 0.03 N/mm 2 when the surface temperature of the waterproofing layer was raised to about $80^{\circ}C$. (2) when the temperature of the fluid-applied membrane of the waterproofing layer was raised from $30^{\circ}C$ to $35^{\circ}C$, water vapor pressure of about 0.01 N/mm 2 was generated, and (3) when a thermal source was applied to the fluid-applied membrane (waterproofing) layer, the temperature increased from $35^{\circ}C$ to $40^{\circ}C$, and approximately $0.005\;N/mm^2$ of water vapor pressure was generated.

• Journal of the Korean Institute of Navigation
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• v.19 no.4
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• pp.83-92
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• 1995

In this study, a vertical type LPE system has been developed for III-V semiconductor compounds single crystal growth. On the basis of the experience & basic study using this system, the system modification has been carried out for a ultra thin multi-layer single crystal. The temperature fluctuation was within ${\pm}0.006^{\circ}C$ at $800^{\circ}C$, temperature uniformity for graphite boat around was within ${\pm}0.15^{\circ}C$ at $650^{\circ}C$, and cooling rate was controllable from $2.2^{\circ}C$/min to $0.05^{\circ}C$/min. As a result it is considered to satisfy the condition to grow a ultra thin layer single crystal of III-V semiconductor compounds.

• Transactions on Electrical and Electronic Materials
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• v.11 no.5
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• pp.222-225
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• 2010

The preparation of tin oxide thin films by atomic layer deposition (ALD), using a tetrakis (ethylmethylamino) tin precursor, and the effects of a seed layer on film growth were examined. The average growth rate of tin oxide films was approximately 1.2 to 1.4 A/cycle from $50^{\circ}C$ to $150^{\circ}C$. The rate rapidly decreased at the substrate temperature at $200^{\circ}C$. A seed effect was not observed in the crystal growth of tin oxide. However, crystallinity and the growth of seed material were detected by XPS after thermal annealing. ALD-grown seeded tin oxide thin films, as-deposited and after thermal annealing, were characterized by X-ray diffraction, atomic force microscopy and XPS.

• Korean Journal of Materials Research
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• v.11 no.9
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• pp.776-780
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• 2001

$SiO_2$ and polycrystalline Si layers were sequentially grown on (100) Si. NiSi was formed on this substrate from a 20nm Ni layer or a 20nm Ni/5nm Ti bilayer by rapid thermal annealing (RTA) at $300~500^{\circ}C$ to compare thermal stability. In addition, MOS capacitors were fabricated by depositing a 20nm Ni layer on the Poly-Si/$SiO_2$substrate, RTA at $400^{\circ}C$ to form NiSi, $BF_2$ or As implantation and finally drive- in annealing at $500~800^{\circ}C$ to evaluate electrical characteristics. When annealed at $400^{\circ}C$, NiSi made from both a Ni monolayer and a Ni/Ti bilayer showed excellent thermal stability. But NiSi made from a Ni/Ti bilayer was thermally unstable at $500^{\circ}C$. This was attributed to the formation of insignificantly small amount of NiSi due to suppressed Ni diffusion through the Ti layer. PMOS and NMOS capacitors made by using a Ni monolayer and the SADS(silicide as a dopant source) method showed good C-V characteristics, when drive-in annealed at $500^{\circ}C$ for 20sec., and$ 600^{\circ}C$ for 80sec. respectively.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2003.05a
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• pp.54-54
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• 2003

MgO layer는 POP 패빌 내 유전증을 이온의 스퍼터링으로부터 보호하여 주며, 또한 높은 이차 전자 밤출 계수의 특성을 가지고 있어 구동 및 유지 전압을 낮춰 주는 역할을 한다. 그러나. MgO layer는 $H_20,{\;}CO_2,{\;}N_2,{\;}0_2$ 그리고 $H_2$와 같은 불순물 들을 쉽게 를착하는 단점이 있어, PDP의 특성 및 수명 단축에 영향을 줄 수 있다. 따라서, 본 연구에서는 atmospheric pressure plasma cleaning 과 low pressure i inductively coupled plasma (ICP) cleaning 처리에 의하여, 보호층으로 사용이 되는 MgO layer의 outgassing 특성을 조사하고자 한다. plasma cleaning에 의한 MgO layer 표면의 roughness와 불순물의 변화를 알아보기 위 하여 atomic force microscopy(AFM)과 x-ray p photoelectron spectroscopy(XPS)를 이용하여 측정 하였다. 또한, outgassing의 특성을 분석하기 위하여 MgO layer를 $400^{\circ}C$ 까지 온도를 가하여 온도에 따른 outgassing의 특성을 quadrupole mass spectrometer(QMS)를 이용하여 알아보았다. atmospheric pressure plasma cleaning 에서는 $He/O_2/Ar/N_2$의 gas를 사용하였으며, low pressure ICP cleaning 에 서는 Ar의 gas를 사용하였다. atmospheric pressure plasma cleaning는 low pressure ICP C cleaning과 비교해 더 낮은 outgassing을 관잘 할 수 있었으나. MgO 표면의 roughness는 low pressure ICP cleaning 후 더 낮은 것을 알 수 있었다. 또한 $He/O_2/Ar/N_2$의 gas를 사용 한 atmospheric pressure plasma cleaning 과 $Ar/O_2$의 gas를 사용한 ICP cleaning에서 이 차전자방출계수(SEEC)가 약 1.5~2.5배 증가된 것을 알 수 있었다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2003.05a
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• pp.518-521
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• 2003

Bi$_2$Sr$_2$Ca$_{n-1}$Cu$_{n}$O$_{x}$ superconducting thin films have been fabricated by atomic layer-by-layer deposition using IBS(Ion Beam Sputtering) method. During the deposition, 90 mol% ozone gas of typical pressure of 1~9 $\times$ 10$^{-5}$ Torr are supplied with ultraviolet light irradiation for oxidation. XRD and RHEED investigations reveal out that a buffer layer with some different compositions is formed at the early deposition stage of less than 10 units cell and then Bi-2201 oriented along the c-axis is grown.grown.

• Journal of the Korean institute of surface engineering
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• v.28 no.3
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• pp.142-151
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• 1995

In this research, a thin layer of Cr was coated on the pure Ni and Inconel 601 by PECVD (Plasma Enhanced Chemical Vapor Deposition) in order to study the effect of Cr on the oxidation behavior at high temperature. Cr coated Inconel 601, which was oxidized at $1100^{\circ}C$ for 24 hours, formed a protective $Cr_2O_3$ oxide layer and the resistance to isothermai oxidation was improved. On the other hand, oxidation resistance of Cr coated Inconel 601 at 100$0^{\circ}C$ was not significantly improved, probably due to the formation or insufficient $Cr_2O_3$ layer. But, when oxidized at $1000^{\circ}C$ and $1100^{\circ}C$ for 100 hours, Cr coated Inconel 601 improved isothermal oxidation resistance by the formation of continuous $Cr_2O_3$ external scale and by the development of $Al_2O_3$ subscales. Cr coated Ni formed inner layer of $Cr_2O_3$ within almost pure NiO, which provided additional cation vacancies, thus increasing the mobility of Ni ions in this region. It is believed that this doping effect resulted in an increase in the observed oxidation rate compared with pure Ni and did not improve the oxidation resistance.

• Korean Journal of Metals and Materials
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• v.47 no.11
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• pp.716-721
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• 2009

The major drive for the application of low-temperature plasma treatment in nitrocarburizing of austenitic stainless steels lies in improved surface hardness without degraded corrosion resistance. The low-temperature plasma nitrocarburizing was performed in a gas mixture of $N_{2}$, $H_{2}$, and carbon-containing gas such as $CH_{4}$ at $450^{\circ}C$. The influence of the processing time (5~30 h) and $N_{2}$ gas composition (15~35%) on the surface properties of the nitrocarburized layer was investigated. The resultant nitrocarburized layer was a dual-layer structure, which was comprised of a N-enriched layer (${\gamma}_N$) with a high nitrogen content on top of a C-enriched layer (${\gamma}_C$) with a high carbon content, leading to a significant increase in surface hardness. The surface hardness reached up to about $1050HV_{0.01}$, which is about 4 times higher than that of the untreated sample ($250HV_{0.01}$). The thickness of the hardened layer increased with increasing treatment time and $N_{2}$ gas level in the atmosphere and reached up to about $25{\mu}m$. In addition, the corrosion resistance of the treated samples without containing $Cr_{2}N$ precipitates was enhanced than that of the untreated samples due to a high concentration of N on the surface. However, longer treatment time (25% $N_{2}$, 30 h) and higher $N_{2}$ gas composition (35% $N_{2}$, 20 h) resulted in the formation of $Cr_{2}N$ precipitates in the N-enriched layer, which caused the degradation of corrosion resistance.

• Korean Journal of Remote Sensing
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• v.5 no.1
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• pp.57-67
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• 1989

This study on the southern coastal waters of Korea has been made by analysis of NOAA image and oceanographic observation data from October 1987 to August 1988. The results obtained from the study are as follow: Horizontal distributions of water temperature in different layers in winter ranged from 6.07 to 18.62$^{\circ}C$ at 0m layer, 6.02 to 18.54$^{\circ}C$ at 30m layer and 7.19 to 18.69$^{\circ}C$ at 50m layer. Consequently its vertical distribution showed homogeneity. Horizontal water temperature gradients were 0.28$^{\circ}C$/mile between the coastal waters and Tsushima warm waters. In summer, its horizontal distribution varied from 19.37 to 29.92$^{\circ}C$ at 0m layer, 13.26 to 27.11$^{\circ}C$ at 30m layer and 7.36 to 26.6$0^{\circ}C$ at 50m layer, and its vertical profile showed stratified structure. Vertical water temperature gradients were 0.44$^{\circ}C$/m between 30 and 50m layers. It was remarkable that distribution of southern coastal water system analysed by NOAA image coincided with relatively the oceanographic observation data but SST from NOAA image seemed to be 2-4$^{\circ}C$ lower in winter and 4-6$^{\circ}C$ lower in summer than the oceanographic data.