• Proceedings of the IEEK Conference
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• 2000.11b
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• pp.29-32
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• 2000

Meta1-ferroelectric-insulator-semiconductor(MFIS) devices using Pt/LiNbO$_{3}$/AIN/Si structure were successfully fabricated. AIN thin films were made into metal-insulator-semiconductor(MIS) devices by evaporating aluminum in a dot array on the film surface. The dielectric constant of the AIN film calculated from the capacitance in the accumulation region in the capacitance-voltage(C-V ) characteristic is 8. The gate leakage current density of MIS devices using a aluminum electrode showed the least value of 1$\times$10$^{-8A}$ $\textrm{cm}^2$ order at the electric field of 500㎸/cm. A typica] value of the dielectric constant of MFIS device was about 23 derived from 1MHz capacitance-voltage (C-V) measurement and the resistivity of the film at the field of 500㎸/cm was about 5.6$\times$ 10$^{13}$ $\Omega$.cmcm

• Proceedings of the IEEK Conference
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• 2000.11b
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• pp.221-224
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• 2000

We have successfully demonstrated metal-ferroel-ectric-insulator-semiconductor (MFIS) devices using Al/LiNbO$_{3}$/SiN/Si structure. The SiN thin films were made into metal -insulator- semiconductor (MIS) devices by thermal evaporation of aluminum source in a dot away on the surface. The interface property of MFIS from 1MHz & quasistatic C-V is good and the memory window width is about 1.5V at 0.2V/s signal voltage sweep rate. The gate leakage current density of MFIS capacitors using a aluminum electrode showed the least value of 1x10$^{-8}$ A/$\textrm{cm}^2$ order at the electric field of 300㎸/cm. And the XRD patterns shows the probability of applications of LN for MFIS devices for FeRAMs on amorphous SiN buffer layer.

• Proceedings of the IEEK Conference
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• 2003.07b
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• pp.1061-1064
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• 2003

In this paper, we deposited A1$_2$O$_3$ thin film using atomic layer deposition(ALD) method on Ti and fabricated metal-insulator-metal(MIM) capacitor. In the result of this study, the typical deposition rate was about 1.12$\AA$/cycle. About 30 nm of Ti was consumed during deposition and TiO$_{x}$ was formed at the interface of A1$_2$O$_3$ and Ti. Its surface roughness was 1.54nm. The leakage current density was 1.5 nA/$\textrm{cm}^2$. The temperature coefficient of capacitance(TCC) of MIM capacitor was 41 ppm/$^{\circ}C$ at 1MHz and 100 ppm/$^{\circ}C$ at 100 kHz.z.

• ETRI Journal
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• v.25 no.4
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• pp.247-252
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• 2003

This paper presents results from experiments on laser-annealed SiGe-selective epitaxial growth (LA-SiGe-SEG). The SiGe-SEG technology is attractive for devices that require a low band gap and high mobility. However, it is difficult to make such devices because the SiGe and the highly doped region in the SiGe layer limit the thermal budget. This results in leakage and transient enhanced diffusion. To solve these problems, we grew in situ doped SiGe SEG film and annealed it on an XMR5121 high power XeCl excimer laser system. We successfully demonstrated this LA-SiGe-SEG technique with highly doped Ge and an ultra shallow junction on p-type Si (100). Analyzing the doping profiles of phosphorus, Ge compositions, surface morphology, and electric characteristics, we confirmed that the LA-SiGe-SEG technology is suitable for fabricating high-speed, low-power devices.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1992.10a
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• pp.166-171
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• 1992

Mechanical seals are generally used in the fields of industries as sealing devices. The failure of mechanical seals like crack, leakage, breakage fast and severe wear, excessive torque, and squeaking result in big problems. For the development of monitoring system, this study was carried out to identify abnormal phenomina on alumina(AI $\_$2/ O /sub3/) seal ring and resin bonded carbon ring, and to propose the proper parameter for monitoring failure on mechanical seals. Sliding were tests are conducted at 12 experimental conditions that contains 3 different contact pressure and 4 surface conditions. Torque, temperature, and acoustic emission are measured. Optical microstructure and scanning electron microscopy are observed for the wear processing every 10 minute sliding at rotation speed of 1750 RPM.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.1807-1810
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• 2003

The formed tool is used to machine the unique shape of rubber seal for geometrical shaping and reduction of cutting time. The bearing rubber seal produced by hot press forming has complex geometry for the complex geometrical shape to prevent leakage of lubricant oil and influx of the dust effectively. Because it is difficult to machine the unique shape exactly by the conventional tool, the formed tool is used in machining mold of the seal. In this paper, It is performed for selection of the formed tool to investigate cutting edge wear, cutting force, and surface quality. Also, an efficient high precision machining is proposed on the experiment data.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.460-461
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• 2008

The forest fire simulation tests were performed with polymer and porcelain insulators at Gochang testing center. These tests consisted of energizing 90 kV at line-to-ground voltage of 154 kV lines and open flame rising up to $600-630^{\circ}C$ as being measured at insulator surface. Mechanical and electrical characteristics such as specific mechanical load, leakage current, low frequency dry flashover voltage and impulse flashover voltage were analyzed for the polymer insulators before, during and after simulation tests compared with porcelain insulators. At the end of fire simulation tests, there was no detrimental deterioration of any insulators. All insulators passed the criteria of KEPCO specification. This study showed that forest fire simulation had no impact on polymer insulators.

• Journal of the korean academy of Pediatric Dentistry
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• v.11 no.1
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• pp.57-74
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• 1984

The purpose of this descriptive in vitro study were to evaluate the enamel-resin interface of the preventive resin restoration with regard to etching patterns and resin-tag morphology by means of scanning electron microscope. The results were as follows; 1. Three basic etching patterns were appeared simultaneously in a same microscopic section, in concentration between 20-50% phosphoric acid. 2. In 35% orthorhosphoric acid group etched for 60 second, the etching pattern was most prominent and demonstrate closely interdigitated with enamel-resin interface without the evidence of microspace, and the resin tags were longest ranged from 10-15 um in length. 3. This pattern of interface could reduce the incidence of marginal leakage and 2ndary caries formation. 4, The preventive resin restoration could serve as sealing a questionable occlusal surface.

• 한국전산유체공학회:학술대회논문집
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• 2008.03b
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• pp.228-231
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• 2008

Flow fields of a transonic centrifugal compressor are calculated using the commercial CFD code, CFX-TASCflow. Due to the transonic inlet condition, interactions between the shock wave and boundary layers and between the shock wave and tip leakage vortices generate complex flow structures and extra losses. The calculated results show that strong secondary flows due to high curvature and high rotational speed of the impeller. And streamlines near suction surface show that strong radially upward flow develops after the shock between the leading edge locations of main blade and splitter.

• Proceedings of the KSME Conference
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• 2003.11a
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• pp.1180-1185
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• 2003

One of the main degradation of steam generator tubes is stress corrosion cracking induced by residual stress. The resulting damages can cause tube bursting or leakage of the primary water which contained radioactivity. Primary water stress corrosion crack occurs at the location of tube/tubesheet hard rolled transition zone. In order to investigate the effect of shot peening on stress corrosion cracking, stress intensity factors are calculated for the crack which is located in the induced residual stress field.