• Journal of the Korean Vacuum Society
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• v.6 no.S1
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• pp.16-22
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• 1997

ion beam processing of materials for medical application has gained increasing interest in the last decade and the implantation of nitrogen into TI-6AI-4V to improve corrosive-wear performance is currently used for processing of total hip and knee joints. Oxides and nitrides of Ti, Zr, Al, Cr were deposited on TI-6AI-4V substrates by DC magnetron sputtering dual ion beam sputtering and ion beam assisted deposition. The cytotoxicity of these films were investigated by MTT method and showed comparable to untreated TI-6AI-4V Plasm-sprayed hydroxyapatite(HAp) coatings showed excellent cytotoxicity regardless of heat treatment. intermediate layer coatings of nitrides and oxides increased the bond strength of HAp to substrate by intrdducing chemical bond at interface. Heat treatment of HAp coatings also improved the chemical bond at interfaces and increased the bond strength of untreated TI-6AI-4V to 16.4 kg/$\textrm{cm}^2$ but still lower than 33.1 kg./$\textrm{cm}^2$ of ir oxide as a imtermediate layer caoting.

• Journal of Electrical Engineering and Technology
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• v.2 no.4
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• pp.532-536
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• 2007

Carbon nanotube (CNT) properties, produced using a magnetic null discharge (MND) plasma production technology, were investigated. We firstly deposited the Fe layer 200 nm in thickness on Si substrate by the magnetic null discharge sputter method at the substrate temperature of $300도C$, and then prepared CNTs on the catalyst layer by using the magnetic null discharge (MND) based CVD method. CNTs were deposited in a gas mixture of CH4 and N2 at a total pressure of 1 Torr by the MND-CVD method. The substrate temperature and the RF power were $650^{\circ}C$ and 600W, respectively. The characterization data indicated that the proposed source could synthesize CNTs even under relatively severe conditions for the magnetic null discharge formation.

• Journal of Korean Society for Atmospheric Environment
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• v.10 no.3
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• pp.159-169
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• 1994

This paper describes the process of acidic precipitation from the atmosphere to the ground water, The net deposition of wet precipitation to the ground surface is obtained by subtracting the interception loss due to plant leaves and evaporation from the amount of total precipitation. As the water immerses through the vegetation and the different soil layers the various chemical reactions take place. The relationship between the acidic precipitation by increasing industrial emissions and the soil acidification mechanism is discussed. The report focuses on the buffering action that involves the proton budget in soil and rocks. Based on the soil constituents, the six buffer ranges of the soil are classified and each buffering process is illustrated. In addition, the Possibility of the contamination of drinking-water reservoirs by continuous acid burden is emphasized.

• Korean Journal of Crystallography
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• v.14 no.2
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• pp.56-61
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• 2003

Nanocrystalline hydrogenated silicon (nc-Si : H) thin films were deposited at room temperature by plasma enhanced chemical vapor deposition (PECVD): a mixture of SiH₄ and H₂ gas was introduced into the evacuated reaction chamber. When the H₂ gas flow rate was low, the density of Si-H₃ bonds was high in the films. On the other hand, when the H₂ gas flow rate was high, e.g., 100 sccm, a large number of Si-H bonds contributed to the passivation of the surface of the large volume of Si nanocrystallites. The relative fraction of the Si-H₃ and Si-H₂ bonds in the amorphous matrix varied sensitively with the H₂ gas flow rate. The variation was associated with the change in the intensity as well as the wavelength of the main PL peaks, indicating the change in the total volume as well as the size of the Si nanocrystallites in the films.

• 한국정보디스플레이학회:학술대회논문집
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• 2008.10a
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• pp.1445-1447
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• 2008

Micro crystal structure of polycrystalline MgO film is controlled by adjusting the energy of particles arrived at the substrate during deposition. The change of crystal structure affects on the total area of (200) surface where the oxygen vacancies are formed easily, resulting in the change of secondary electron emission (SEE) coefficient($\gamma$).

• 한국정보디스플레이학회:학술대회논문집
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• 2006.08a
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• pp.434-438
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• 2006

High-quality a-Si TFTs were fabricated on 7 inch plastic PES substrates at $130^{\circ}C$ and $100^{\circ}C$. It had been shown that the key factor for successful TFT fabrication on the relatively large plastic substrates is thorough control of total active layer's stress by means of deposition temperature reduction and single layer's intrinsic stress optimization.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.18 no.12
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• pp.1148-1151
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• 2005

Photovoltaic effects in organic solar cell were studied in a cell configuration of ITO/PEDOT:PSS/CuPc(20 nm)/$C_{60}$(40 nm)/BCP/Al(150 nm) at room temperature. Here, the BCP layer works as an exciton blocking layer. The exciton blocking layer must transport electrons from the acceptor layer to the metal cathode with minimal increase in the total cell series resistance and should absorb damage during cathode deposition. Therefore, a proper thickness of the exciton blocking layer is required for an optimized photovoltaic cell. Several thicknesses of BCP were made between $C_{60}$ and Al. And we obtained characteristic parameters such as short-circuit current, open-circuit voltage, and power conversion efficiency of the device under the illumination of AM 1.5.

• Transactions on Electrical and Electronic Materials
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• v.8 no.3
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• pp.115-120
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• 2007

Reliability between passivated and unpassivated process with the base-exposed InGaP/GaAs HBTs was studied. A passivation of HBT was attempted by $SiO_2$ thin film deposition at $300^{\circ}C$ by means of PECVD. Base-exposed InGaP/GaAs HBTs before and after passivation were investigated and compared in terms of DC and RF performance. Over a total period of 30 days, passivated HBTs show only 2% degradation of DC current gain for the high current density of $40KA/cm^2$. The measured thermal resistance of $2{\times}30{\mu}m^2$ single emitter InGaP/GaAs HBT passivated with PECVD $SiO_2$ devices can be extracted and was founded to be 1430 K/W. The estimated MTTF was $2{\times}10^7hr\;at\;T_j=125^{\circ}C$ with an activation energy $(E_a)$ of 1.37 eV.

• Journal of the Korean Society for Precision Engineering
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• v.18 no.3
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• pp.47-52
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• 2001

Rapid Prototyping(RP) has been widely applied in designing and developing process of new products. RP can reduce the lead time and expense required to bring a new product form initial concept to production. Among several RP process can dramatically reduce the total build time and be applied for fabrication of large-sized and free form object because it uses in LOM the paper thickness is 0.05∼0.38mm as deposition feature segment. In this study, mechanical properties of pattern with LOM system is studied for optimal design of sand mold casting. The main result is that tensile, compressive strength and pattern size are significantly affected by temperature of hot roll.

• Journal of the Korean Ceramic Society
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• v.41 no.3
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• pp.247-252
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• 2004

노튜브의 길이는 급격히 증가하였지만 촉매금속의 적층방법에 따른 탄소나노튜브의 성장 형태는 큰 차이가 없었다. 특히, ICBD 방법에 의해 Ni 촉매금속을 증착한 경우 다른 방법에 비하여 직선적인 탄소나노튜브가 관찰되었다. ^x Carbon nanotubes were grown on SiO$_2$/Si substrates by applying $C_2$H$_2$ gas through chemical vapor deposition process. It was found that carbon nanotubes were grown successfully on the substrates with catalytic films under 20 $\AA$ total thickness. The increase in reaction temperature from 50$0^{\circ}C$ to 80$0^{\circ}C$ resulted in longer carbon nanotube, but there was no clear tendencies with different types of catalytic layers. It was evident that carbon nanotubes became more straight on the substrate with Ni catalytic film produced by ICBD method.