• Journal of the Korean Ceramic Society
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• v.32 no.10
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• pp.1103-1110
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• 1995

Silicon carbide (SiC) films have been deposited on the isotropic graphite by chemical vapor deposition. Change of deposition parameters affected significantly the microstructure and preferred orientation of SiC films. Preferred orientation of SiC films was (111) or (220), and microstructure showed the startified structure consisting of small crystallite or faceted columnar structure depending on the deposition parameters. For microhardness, (111) oriented film and stratified structure were superior to (220) oriented film and faceted columnar structure, respectively. Surface of (111) oriented films was less rough than that of (220) oriented films. Adhesion force between graphite substrate and SiC films was above 100N for crystalline films and 49N for amorphous film.

• Proceedings of the Materials Research Society of Korea Conference
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• 2002.11a
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• pp.93-93
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• 2002

• Journal of the Korean Vacuum Society
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• v.15 no.6
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• pp.619-623
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• 2006

The most important factor which determines resonance characteristics of FBAR(Film Bulk Acoustic Resonator) is the piezoelectricity of piezoelectric film. The piezoelectric properties of ZnO thin films which is strong as FBAR piezoelectric film is determined by the degree of c-axis preferred orientation with (002) plan. Therefore, many researchers have been interested in the study on the preferred orientation of the piezoelectric thin film. This paper has studied the preferred orientation of ZnO piezoelectric thin films using the helped seed layer of ZnO. The result shows that the c-axis ZnO thin films with columnar grains that the value of standard $deviation(\sigma)$ of XRD rocking curve is of $\sigma=1.15^{\circ}$ have the excellent piezoelectric property.

• Journal of the Korean Ceramic Society
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• v.33 no.7
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• pp.802-808
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• 1996

PbTiO3 thin films were fabricated onto MgO(100) single crystal substrate by reactive D. C magnetron sput-tering of Pb and Ti metal in an oxygen and argon gas mixture. The annealing of the thin films resulted in the decrease of both the c-axis orientation ratio and the lattice parameter. It is well known that the c-axis lattice parameter of thin film is dependent on the Pb/(Pb+Ti)ratio and the residual stress in the film The PbTiO3 thin films with a Pb/(Pb+T) ratio ranging from 0.45 to 0.57 were fabricated and annealed. The structure of the film the c-axis orientation ratio and the lattice parameter were not dependent on the Pb/(Pb+Ti) ratio before and after annealing. These experimental results proved that the decrease of the c-axis lattice parameter under the annealing conditions was due to the relaxation of the intrinsic stress in the film. This relaxation of the intrinsic stress caused the decrease of the c-axis orientation ratio and this phenomenon can be explained by c-axis growth lattice model.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.07a
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• pp.617-619
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• 2001

The effect of the superconducting film thickness on the substrate temperature has been investigated. Superconducting YBCO thin films have been grown on MgO substrates by pulsed laser deposition. The dependence of the orientation of YBCO film on thickness has been investigated by X-ray diffraction technique. X-ray diffraction indicated that the film orientation was changed by increasing the film thickness and by changing the substrate temperature.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.14 no.5
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• pp.410-416
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• 2001

KLN thin films were fabricated on Pt coated Si(100) wafer using an rf-magnetron sputtering method. The grown KLN thin film consists of 4-fold grains. In this experiment, the structure of 4-fold grained thin film was investigated using XRD and SEM measurements. Pt layer was also deposited using the rf-magnetron sputtering method,. XRD measurement showed that he Pt thin film has Gaussian distribution form with strong (111) direction orientation. The KLN thin film has preferred-orientation of (001) direction, and the peak consists of 2 separate peaks; one with broad FWHM and the other with narrow FWHM. The sharp peak is due to single crystal, and combining with Em results, the 4-fold grain consists of singel crystals with c-axis normal to substrate.

• Journal of the Korean Ceramic Society
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• v.37 no.11
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• pp.1126-1129
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• 2000

The crystallographic orientations of $Ba_{0.6}$S $r_{0.4}$Ti $O_3$(BST) thin film deposited by a metal-organic chemical vapor deposition on (111) textured Pt electrode were studied with a transmission electron microscopy. The fully crystallized BST thin film (50nm) has (100) and (110) preferred orientations. A high resolution transmission electron microscopy study has revealed the crystallographic orientation relationships between BST thin film and Pt electrode. These relationships explained the preferred orientation of BST film on (111) textured Pt electrode. With these results, we could represent the atomic arrangement at the BST/Pt interface.e.e.

• Polymer(Korea)
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• v.34 no.3
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• pp.220-225
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• 2010

The optical properties and dimensional stability of polyethersulfone(PES) retardation film have been studied as function of chain orientation and the temperature applied to PES retardation film. It was confirmed that the appropriate retardation values of $R_e$ and $R_{th}$ for the retardation film application were able to obtain by the chain orientation and these values could be controlled by the chain relaxation through the thermal annealing process. It was found that unstable $R_e$ and $R_{th}$ values were shown by the repeated cooling and heating applied to the retardation films but this could be stabilized by means of the annealing process after stretching of PES film. The dimensional shrinkage due to the chain orientation was found as temperature increase and the intrinsic thermal expansion of PES appeared after shrinking. The shrinkage of PES films affected by the chain orientation and thermal annealing dramatically but the effect on the coefficient of thermal expansion was found to be negligible.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.25 no.8
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• pp.1122-1130
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• 2001

Film cooling performance from two rows of holes with opposite orientation angles is evaluated in terms of heat flux ratio. The film cooling hole has a fixed inclination angle of 35°and orientation angle of 45°for the downstream row and -45°for the upstream row. Four film cooling hole arrangements including inline and staggered configurations are investigated. The blowing ratio studied was 1.0. Boundary layer temperature distributions are measured to investigate injectant behaviors and mixing characteristics. Detailed distributions of the adiabatic film cooling effectiveness and the heat transfer coefficient are measured using TLC(Thermochromic Liquid Crystal). For the inline configuration, there forms a downwash flow at the downstream hole exit to make the injectant well attach to the wall, which gives high adiabatic film cooling effectiveness and heat transfer coefficient. The evaluation of heat flux ratio shows that the inline configuration gives better film cooling performance with the help of the downwash flow at the downstream hole exits.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.25 no.8
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• pp.1131-1139
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• 2001

Experimental results are presented, which describe the effect of blowing ratio on film cooling from two rows of holes with opposite orientation angles. The inclination angle is fixed at 35°, and the orientation angles are set to be 45°for the downstream row, and -45°for the upstream row. The studied blowing ratios are 0.5, 1.0 and 2.0. The boundary layer temperature distributions are measured using thermocouple at two downstream locations. Detailed adiabatic film cooling effectiveness and heat transfer coefficient distributions are measured with TLC(Thermochromic Liquid Crystal). The adiabatic film cooling effectiveness and heat transfer coefficient distributions are discussed in connection with the injectant behaviors inferred from the boundary layer temperature distributions. Film cooling performance, represented by heat flux is evaluated from the adiabatic film cooling effectiveness and heat transfer coefficient data. The results show that the investigated geometry provides improved film cooling performance at the high blowing ratios of 1.0 and 2.0.