• Proceedings of the KWS Conference
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• 2003.11a
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• pp.33-35
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• 2003

• Journal of Welding and Joining
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• v.23 no.3
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• pp.21-25
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• 2005

• Proceedings of the Korean Vacuum Society Conference
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• 2002.02a
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• pp.127-127
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• 2002

• Proceedings of the Optical Society of Korea Conference
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• 2002.11a
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• pp.110-111
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• 2002

• Proceedings of the KIEE Conference
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• 1999.07d
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• pp.1849-1851
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• 1999

The PDP(Plasma Display Panel) barrier rib was fabricated by focused $Ar^+$ laser ($\lambda$=514nm) and Nd:YAG($\lambda$=532, 266 nm) laser irradiation. The depth of the etched groove increases with increasing a laser fluence. and decreasing a scan speed. Using the second harmonic of the Nd:YAG laser, the threshold laser fluence was $6.5mJ/cm^2$ for the sample of PDP barrier rib dried at $120^{\circ}C$. The thickness of $150{\mu}m$ of the sample on the glass was etched without any damage on the glass substrate by fluence of $19.5J/cm^2$. The barrier rib sample on hot plate was etched by Nd:YAG laser(532 nm) as increasing a temperature of the sample. In this case, the etch rate was $95{\mu}m/s$, $190{\mu}m/s$ at room temperature, $175^{\circ}C$ respectively.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.22 no.4
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• pp.680-685
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• 2013

In this study, the effect of laser shock peening on a titanium alloy was modeled using different confinements. Both liquid and solid confinement could be applied to laser shock peening, and solid confinement provided a dry laser shock peening process, which has the advantage of a corrosion-free effect. When a different confinement was applied to laser shock peening, a different peening effect would be expected. In our study, the peening effect was numerically modeled and simulated. The main effect of different confinements was a change in the impedances required to confine a shock wave from a plasma. The impedances were assumed with respect to different materials. Johnson-Cook's plastic deformation modeling was applied to the simulation. The strains and residual stresses were calculated to evaluate the confinement effects. When solid confinement was used, the residual stress increased by 60-85%, compared to the case of liquid confinement. However, the depth of the residual stress was slightly deeper. The simulated results could be applied to estimate the peening effect when a different confinement was used in the laser shock peening process.

• Proceedings of the Korean Society of Laser Processing Conference
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• 2006.11a
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• pp.17-20
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• 2006

In the remote welding system using $CO_2$ laser, laser beam is rapidly deflected by moving mirrors of scanner system and has focusable distance over 1000mm from workpiece. From such arrangement, various advantages and disadvantages arise. Remote welding is a highly efficient laser process. As the mirrors of the scanner system allow positioning speeds exceeding 700m/s, it becomes possible to reduce the welding cycle time. On the other hand, as there no the provision of shielding gas which is normally required for beam powers exceeding 3kW, may become difficult task. Therefore, In this study, the influence of the various penetration of back bead by the different laser welding speed on the weld seam formation without shielding gas was investigated.

• Proceedings of the KIEE Conference
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• 1991.07a
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• pp.191-193
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• 1991

In this paper, we introduce silicon dioxide films deposited by Laser CVD, and evaluate the breakdown characteristics of these films by TZDB(Time Zero Dieiectric Breakdown) and TDDB(Time Dependent Dielectric Breakdown) test, failure times against eletric field are examined and accelation factors ${\beta}$ are obtained, and also, long term reliability is described by examining TDDB under positive voltage bias, all the above results are compared with PECVD(Plasma Enhanced CVD) $SiO_2$ breakdown, data, as a result, it is shown that the breakdown characteristics of Laser CVD $SiO_2$ films is improved.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.04c
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• pp.22-26
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• 2008

In this paper, we developed a hybrid simulation model of carbon laser ablation under the Ar plasmas consisted of fluid and particle methods. Three kinds of carbon particles, which are carbon atom, ion and electron emitted by laser ablation, are considered in the computation. In the present simulation, we adopt capacitively coupled plasma with asymmetrical electrodes. As a result, in Ar plasmas, carbon ion motions were suppressed by a strong electric field and were captured in Ar plasmas. Therefore, a low number density of carbon ions were deposited upon substrate. In addition, the plume motions in Ar gas atmosphere was also discussed.

• 한국정보디스플레이학회:학술대회논문집
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• 2002.08a
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• pp.689-691
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• 2002

Well-aligned multi-wall carbon nanotubes (MWCNTs) have been grown on both Coming glass and silicon substrates at about 400 $^{\circ}C$ by a modified plasma - enhanced chemical vapor deposition system. We have investigated laser irradiation effect on carbon nanotube surface by using an ultra - violet laser. The laser operated to modify structural defect of was carbon nanotube and to ablate possible contamination of carbon nanotube surface. The morphology and surface transformation of MWCNTs as analyzed by a SEM. In addition, the field emission measurement was also carried out in a vacuum chamber with a $10^{-7}$ Torr base pressure by applying bias voltages up to 1000V.