• Tribology and Lubricants
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• v.11 no.3
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• pp.24-30
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• 1995

This paper was undertaken to recognize the pattern of the wear debris by neural network as a link for the development of diagnosis system for movable condition of the lubricated machine surface. The wear test was carried out under different experimental conditions using the wear test device was made in laboratory and wear testing specimen of the pin-on-disk type were rubbed in paraffine series base oil, by varying applied load, sliding distance and mating material. The neural network has been used to pattern recognition of four parameter (diameter, elongation, complex and contrast) of the wear debris and learned the friction condition of five values (material 3, applied load 1, sliding distance 1). The three kinds of the wear debris had a different pattern characteristic and recognized the friction condition and materials very well by the neural network. The characteristic parameter of the large wear debris over a few micron size enlarged recognition ability.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.07b
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• pp.1058-1061
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• 2003

In this thesis, we observed the optical characteristic of amorphous chalcogenide thin films by He-Cd laser. Also, grating formation by He-Ne laser and He-Cd laser. After analyze diffraction efficiency of the time on the $Ag(200{\AA})/As_{40}Ge_{10}Se_{15}S_{35}$ thin films. The result diffraction efficiency of Maximun 0.2% reduced according to time grating formation by He-Ne laser. Diffraction efficiency of Maximun 0.1% showed stabiliy characteristic according to time grating formation by He-Cd laser.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.07b
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• pp.1047-1049
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• 2003

Stibenequinone(SQ) derivative which was electronic transportation materials in Poly(N-vinylcarbazole) (PVK)-based on organic EL and an optical characteristic of organic EL which is mentioned previously was investigated. The Photoluminescence highest pick with blending TBSQ with PVK was shifted from 439nm to 517nm. This result indicates that an energy gap of a PVK/TBSQ blended sample is less than an energy gap of PVK. According to the electrochemistry characteristic, the ionization energy(Ip) and the electro affinity(Ea) decreased from 5.79eV to 5.63eV and 2.23eV to 2.63eV, respectively.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.07b
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• pp.744-746
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• 2003

A ZnO varistor with reference voltage 250V/mm was fabricated through the control of particle size in slurry and the variation of sintering conditions. It was found that to measure the flatness of the V-I characteristic curve in the small-current region and the flatness of the V-I characteristic curve in a large-current region was improved nonlinearity of the fabricated ZnO varistor. According to the IEC 60099-4 was measured the accelerated aging test and high current test of the distribution class surge varistor which is excellent in respect to the property of ZnO varistor.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2010.06a
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• pp.173-173
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• 2010

We proposed viewing angle switchable liquid crystal display(LCD) associated with fringe-field switching (FFS) mode with high aperture ratio characteristic. In the device, single pixel is separated into two regions, named as main pixel for displaying images and sub pixel for viewing angle control. In sub pixel region, add the common electrode on the top substrate and the initial alignment of liquid crystal is Hybrid Alignment Nematic (HAN) state. In conclusion, we suggested that the device has high aperture ratio characteristic because the LC directors are rotated in which viewing angle control region are generated fringe electric field.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.11a
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• pp.113-114
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• 2008

Conventional furnace annealing (CFA) for activating Mg-doped p-type GaN films had been performed in pure $N_2$ ambient. All sample activated the same gas ambient. The annealing process change temperature: the first process is performed at $550^{\circ}C$ for 10 min. but, the first process is the same bulk. From second to five process increase activation temperature to change $50^{\circ}C$ and annealing time keeping for 10 min. It is found that the samples characteristic measure hall measurement. Similar results were also evidenced by photoluminescence (PL) measurement.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2008.04a
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• pp.1005-1009
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• 2008

The high efficiency insulation panel for transformer construction is needed in residential area because the making noise from transformer substation in side of city is appeared a lost of problem by increasing to conserve the living environment. Therefor in this paper, first the vibration and noise characteristic of existing insulation panel is analyzed according to attached material, cork and sponge-type. Second the insulation of sound performance is compared between the existing insulation panel. And high efficiency insulation panel that is proposal in this paper.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2000.05a
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• pp.874-877
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• 2000

Pre-coated sheet materials are a cost-effective and environmentally attractive alternative to conventional sheet materials coated after forming. At present but the high scratch sensitivity of coating used for pre-coated metal sheet is a major limitation to use of these materials. Because of high scratch sensitivity, products made by pre-coated metal sheet are not formed by conventional design method. This study has been performed to investigate scratch characteristic of non-vinyl pre-coated metal (PCM) sheet. Using the simple U-bending test equipment, three non-vinyls PCM's were tested. This paper provides the results of bending tests showing the influence of sheet surface texture, tool material and process conditions. It was found that the influence of punch, die clearance and tool material had an effect upon the scratch characteristic.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.04b
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• pp.97-100
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• 2004

We have grown GaN layers with in-situ SiN mask by metal organic chemical vapor deposition (MOCVD) and study the characteristic of the GaN layer. We have changed the deposition time of SiN mask from 45s to 5min and obtain th optimum condition in 45s. The PL intensity of GaN with SiN mask improved 2 times to that without SiN mask and the carrier concentraion increased from $3.5{\times}10^{16}cm^{-3}$ to $1.8{\times}10^{17}cm^{-3}$. We have thus shown that the SiN mask improved significantly the optical properties of the GaN layer.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.29 no.8 s.239
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• pp.1139-1145
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• 2005

Most failures of ductile materials in metal forming processes occurred due to material damage evolution - void nucleation, growth and coalescence. In this paper, the modified yield function of Liao et al in conjunction with the Hosford's yield criterion is studied to clarify the plastic deformation characteristic of voided anisotropic sheet metals. The void growth of an anisotropic sheet under biaxial tensile loading and damage effect of void growth on forming limits of sheet metals are investigated. Also the characteristic length defining the neck geometry is introduced in M-K model to incorporate the effect of triaxial stress in necked region on forming limits. The forming limits theoretically predicted are compared with experimental data. Satisfactory agreement was obtained between the predictions and experimental data.