• Proceedings of the Korean Society of Laser Processing Conference
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• 1998.05a
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• pp.54-55
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• 1998

• Proceedings of the Korean Society of Laser Processing Conference
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• 1998.11a
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• pp.20-23
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• 1998

• Proceedings of the Optical Society of Korea Conference
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• 2002.11a
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• pp.90-91
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• 2002

• Journal of the Korean Ceramic Society
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• v.34 no.10
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• pp.1015-1020
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• 1997

In the Nd;YAG crystal growth by Czochralski method, the relationship between the core formation and the solid-liquid interface was observed by controlling the temperature gradient in the furnace. When the crystal was grown along<111> direction, defects and core area were reduced as the temperature gradient increased. The optimum temperature gradient was found to be higher than 4$0^{\circ}C$/cm. The Nd3+ concentration analysis by ICP-Mass showed that the segregation coefficient was about 20% higher in the core region than core-free region, where the segregation coefficients of core region and core-free region were 0.22 and 0.18, respectively.

• Korean Journal of Crystallography
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• v.7 no.1
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• pp.1-7
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• 1996

We developed an automatic diameter control system to control the diameter of single crystal for Czochralski growth. The system is composed of load cell, software program and data acquisition system connected to computer which controls RF power. This study describes the basic principle, characteristics and components of the system. The diameter of Nd:YAG crystal could be controlled within ±5% tolerance by this system.

• 전기의세계
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• v.42 no.3
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• pp.19-27
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• 1993

본고에서는 Nd:YAG 레이저의 구조 및 특성에 대하여 설명한 뒤 그 제작 및 응용기술에 대한 이해를 돕고자 한다. 제2장에서는 일반적으로 레이저에 대하여 잘 모르는 사람이 이해하기 쉽도록 발전원리에 대하여 간략하게 기술한 후, YAG 레이저의 구조 및 특징에 대하여 간략하게 기술하고 YAG레이저의 구조 및 특징에 대하여 설명하고자 한다. 제3장에서는 전기연구소에서 수행한 YAG 레이저의 설계 및 제작기술, 그리고 연구결과에 대하여 간략히 설명하고 제4장에서는 그 응용기술에 대하여 설명한다. 제5장은 본고에서 기술한 내용을 정리함과 동시에 금후의 발전방향에 대하여 이야기 하고자 한다.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2007.11a
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• pp.193-194
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• 2007

• Korean Journal of Optics and Photonics
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• v.20 no.5
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• pp.276-280
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• 2009

A Cr:YAG crystal was used as a saturable absorber for passive Q-switching of a Nd:$YVO_4$ laser which was pumped by a 1-W continuous wave laser diode. The first surface of the Cr:YAG was high-reflection coated for the pump wavelength. The high-reflection coating improved the absorption efficiency of the pump beam in the Nd:$YVO_4$ through double pass absorption. It also prevented pump beam induced partial bleaching of the Cr:YAG. The peak-to-peak pulse fluctuation of passively Q-switched laser output was approximately 4 %. The minimum pulse-width was measured to be 7.11 ns. Also, the average pulse repetition rate was 9 kHz and the maximum output power was 16.27 mW.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.04a
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• pp.129-132
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• 2000

The PDP(Plasma Display Panel) barrier rib material on the glass substrate was patterned for fabrication of the PDP cell using Nd:YAG laser(1064 nm) which can generate the second(532 nm) and forth(266 nm) harmonic wave by HGM(harmonic generation modules). At a scan speed of 20 ${\mu}m/s$ with the second harmonic wave(532 nm) of Nd:YAG laser, the etching threshold laser fluence of the PDP material was 6.5 $mJ/cm^2$ and a sample(thickness = 180 ${\mu}m$) on the glass substrate was removed clearly at a laser fluence of 19.5 $mJ/cm^2$. In order to increase the throughput of the fabrication we divided a single-beam into multi-beams by using a metal mask between the sample and the focusing lens. As a result, 10 lines of PDP cell were formed by one laser beam scanning at a scan speed of 200 ${\mu}m/s$ and a laser fluence of 2.86 $J/cm^2$.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.12 no.3
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• pp.58-67
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• 2003

Welding characteristics of austienite 304 stainless and SM45C using a continuous wave Nd:YAG laser n experimentally investigated Laser beam welding is increasingly being used in welding of structural steels. The laser welding process is one of the most advanced manufacturing technologies owing to its high speed and deep penetration. The thermal cycles associated with laser welding are generally much Inter than those involved in conventional welding processes, leading to a rather small weld zone. Experiments are performed for 304 stainless steel plates changing several process parameter such as laser power, welding speed, shielding gas flow rate, presence of surface pollution, with fixed or variable gap and misalignment between the similar and dissimilar and plates, etc. The Nd:YAG laser welding process is one of the most advanced manufacturing technologies owing to its high speed and penetration. This paper describes the weld ability of SM45C carbon steel for machine structural use by Nd:YAG laser. The follow conclusions can be drawn that laser power and welding speed have a pronounced effect on size and shape of the fusion zone. Increase in welding speed resulted in an increase in weld depth/aspect ratio and hence a decrease in the fusion zone size. The penetration depth increased with the increase in laser power.