• KSTLE International Journal
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• v.1 no.2
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• pp.83-90
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• 2000

The surface roughness between a piston ring pack and a cylinder liner directly affects the fuel economy, the oil consumption, and the emission of the engine so that it is very important to clarify the surface roughness effects on the lubrication characteristics. The friction characteristics of the piston ring during engine operations are known to as mixed lubrication experimentally. In this study to simulate the effects of the surface roughness of the piston ring pack on the lubrication characteristics, the mixed lubrication analysis of piston rings was performed using the simplified average Reynolds equation. From the results the surface roughness was found be considerably affects minimum oil film thickness as well as FMEP(Friction Mean Effective Pressure). Especially, the oil ring was the most sensitive on the surface roughness.

• Proceedings of the Materials Research Society of Korea Conference
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• 1992.05a
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• pp.6-6
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• 1992

Ionized cluster beam deposition (ICBD) technique has been employed to fabricate high-purity crystalline polyimide (PI) film. The pyromellitic dianhydride (PMDA) and oxydianiline (ODA) were deposited using dual ICB sources, Fourier trans forminfraredspectroscopy (FT-IR), X-ray photoemission spectroscopy (XPS), and Transmission electron microscopy (TEM)study show that the bulk and surface chemical properties and the crystalline structure are very sensitive to the ICBD conditions such as cluster ion acceleration voltage and ionization voltage, At optimum ICBD conditions, the PI films have a maximum imidization, negligible impurities(∼1% isoimide), and a good crystalline structure probably due to the high surface migration energy and surface cleaning effect. These characteristics are superior to those of films deposited by other techniques such as colvent cast, vapowr deposition, or sputtering techniques.

• Journal of Magnetics
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• v.5 no.2
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• pp.55-58
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• 2000

Local magnetic properties and magnetization distributions on the air-bearing surface of a thin-film magnetic head have been studied by using scanning magneto-optical Kerr microscopy. The examined head was a merged MR read/inductive writing head with a write gap equal to 0.3 $\mu m$. Sizes of top and bottom pole-tips on the air-bearing surface of the writing head were equal to $3\mu m\times3\mu m$ and $3\mu m\times30\mu m$, respectively, The measured magnetic characteristics on the head air-bearing surface were found to be very sensitive to the head design. In particular, magnetization distributions were discovered to have asymmetrical shape. Maximum magnitudes of the magnetization were located near the shorten pole-tip. So, it was experimentally proved that more magnetic flux emanates just from this part of the air-bearing head surface.

• 한국정보디스플레이학회:학술대회논문집
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• 2008.10a
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• pp.1233-1236
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• 2008

This study presents the fabrication process and display characteristics of a flexible organic polymer display device that consists of a thin substrate of Polyether Sulfone, a multilayer serpentine-type microheater array that is fabricated on the substrate, and a UV-sensitive polydiacetylene (PDA)-polyvinyl alcohol (PVA) composite film. A retention time of one second is achieved with cell sizes of $500{\mu}m$ and $700{\mu}m$ with cell-to-cell distances of $100{\mu}m$ and $200{\mu}m$, respectively.

• Journal of the Korean Ceramic Society
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• v.37 no.6
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• pp.537-544
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• 2000

Thin-film humidity sensor which TiO2, ZrO2, or CeO2 was added to MgCr2O4-based materials, respectively, were fabricated on the alumina substrate by using a resistant-heating evaporator. Thin films were approximately 2${\mu}{\textrm}{m}$ in grain size and shwoed porous microstructures. The resistance of the sensor decreased with increasing the relative humidity and the MgCr2O4-TiO2 sensor had the best humidity-sensing characteristics (linearity in relative humidity versus resistance).

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.05b
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• pp.323-326
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• 2000

In this study, we used Brewster-Angle Microscope(BAM) to study on the molecular orientation of monolayer on the water surface. The behaviors of molecules on three different subphase have been observed. Reproducible $\pi$-A isotherm have been obtained only on information about phase transition by molecular area. BAM facilitates the observation of morphology by optical anisotropy and thickness in monolayer and multilayers as BAM is shown to be sensitive to anisotropy of film. Every transition was found by BAM technique, either as a dramatic change in degree of contrast or as a sudden alteration of molecular action and $\pi$-A isotherm.

• Textile Coloration and Finishing
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• v.3 no.4
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• pp.22-28
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• 1991

Perfluoropropene was plasma polymerized in the form of thin film on PET fabrics to give hydrophobic and barrier properties without affecting air permeability. Changes in surface characteristics were detected by application of ESCA, IR, SEM and contact anglemeter. The surface properties was changed markedly to be water and stain repellent although the effect was not much sensitive to the differences of chemical components of the thin films formed at different experimental conditions. The protective barrier characteristics of the thin film was also applicable to suppress the amounts of dyes extracted from fabrics in laundering.

• Transactions of the Korean hydrogen and new energy society
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• v.6 no.1
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• pp.17-22
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• 1995

Thermally evaporated Pd films on substrate were hydrogenated upto 1 bar of hydrogen gas at room temperature. Temperature dependence hange of electrical resistivity on Pd films is examined in the thickness range between $60{\AA}$ and $990{\AA}$. Resistivity of Pd is fitted well with Bloch-$Gr{\ddot{u}}neisen$ formula. Debye temperatures of Pd films are about 254 K, which are 20 K lower than that of bulk Pd. Debye temperature is not sensitive to film thickness change. Temperature of substrate during evaporation changes temperature dependence of resistivity of films much. Optical phonon contribution increases with decreasing temperature of PdHx.

• Proceedings of the KIEE Conference
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• 1996.07c
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• pp.1716-1718
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• 1996

It is well known that the metallophthalocyanine (MPcs) are sensitive to toxic gaseous molecules such as $NO_2$ and also chemically and thermally stable. Therefore, lots of MPcs are studied for the potential chemical sensor for $NO_2$ gas using quartz crystal microbalance(QCM) or electrical conductivity. In this study, thin films of octa(2-ethylhexyloxy) copper-phthalocyanine were prepared by Langmuir-Blodgett method and characterized by using UV-VIS spectrascopy and ellipsometry. Transfer condition, film characterization, and preliminary results of current-voltage(I-V) characteristics of these films exposed to $NO_2$ gas as a function of film thickness will be discussed.

• Transactions on Electrical and Electronic Materials
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• v.15 no.3
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• pp.136-138
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• 2014

In this study, cholesterol sensors consisting of a mixture of cholesterol oxidase (ChOx) and zinc oxide (ZnO) nanoparticles (NPs) are constructed on plastic substrates and their sensing characteristics are examined in air. The current of the ChOx-ZnO NP film decreases in magnitude as cholesterol molecules are adsorbed on the film, due to the resulting increase in the number of electrons generated by the reaction between the cholesterol and the ChOx. The cholesterol sensor shows a high sensitivity of $1.08{\mu}A/mM$ and a wide detection range from 10 nM to 1 mM.