• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 2008년도 춘계학술대회 논문집 센서 박막재료연구회 및 광주 전남지부
• /
• pp.22-26
• /
• 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.

• 전자공학회논문지A
• /
• 제32A권1호
• /
• pp.119-128
• /
• 1995

We report hybrid and passive mode-locking results of tilted-stripe AlGaAs semiconductor laser traveling wave amplifiers with saturable absorbers. Dependence ofthe pulse width on the mode locking frequency, the bandwidth of spectral filters, and the bias current of the laser amplifier are investigated. We generate 4 ps optical pulses by using the hybrid mode locking technique. The repetition rate and the peak power of generated pulses are 516 MHz and 170 mW, respectively. The tuning range of uor mode locked laser is 10 nm with the center wavelength of 780 nm. We also generate 2.6 ps optical pulses with peak power of 830 mW by using the passive mode locking technique.

• 한국생산제조학회지
• /
• 제23권5호
• /
• pp.525-531
• /
• 2014

A cowl cross is a part of the car's instrument panel used to maintain the rigidity of the vehicle body side. The application of laser welding has the benefits of speed and thermal deformation compared to arc welding. An ultra-high strength steel sheet is used to reduce the weight of the vehicle body parts. Generally, formability of such a steel sheet is poor because its elongation is very low. For this reason, a method for cold forming of an ultra-high strength steel sheet is required. This paper describes how to improve the formability and weldability of the ultra-high strength steel sheet. Mechanical tests of this material were also performed to evaluate the welding properties of $CO_2$ (GMAW) and those of laser welding.

• 한국기계가공학회지
• /
• 제20권7호
• /
• pp.97-104
• /
• 2021

LASOX is a cutting technology used to dismantle nuclear power plants. The core component of the laser-assisted oxygen hybrid cutting process is the supersonic nozzle. To design optimized supersonic nozzles, an experimental design was established and computational fluid dynamics was used to analyze the supersonic nozzles. The main factors affecting the supersonic nozzle performance were identified using Minitab. Further, the correlations and interactions between the main factors of the supersonic nozzle design were analyzed. The fluid analysis results were examined for the major factors and standardized response variables as well as main effects to ensure suitability of the supersonic nozzle design for the laser-assisted oxygen cutting process.

• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 2002년도 추계학술대회논문집
• /
• pp.782-787
• /
• 2002

In optical disk drives (ODD), the demands of high data density and high speed have been increasing rapidly to achieve high data capacity and data transfer rate. The short wavelength laser, High NA objective lens, and high track following performance are needed to raise data density and data rate. For high-performance actuator, the improvement of linearity and acceleration become more important. Also, 3-axis actuator for active tilt compensation is introduced to overcome the decrease in disk tilt tolerance which is induced by short wavelength laser. In this paper, a hybrid type 3-axis actuator is presented and a new yoke structure, which can reduce the interaction between yoke and moving magnet, is designed to keep the efficiency of magnetic circuit. Experimental results show the validity of the yoke in the hybrid type actuator.

• 한국정밀공학회지
• /
• 제27권10호
• /
• pp.7-13
• /
• 2010

We report a hybrid DPSSL with a pulse parameter variable LD seed, all-fiberized polarization-maintained pulsed Yb-doped fiber preamplifier chains, and a bulk Nd:$YVO_4$ power amplifier. Pulse parameter of LD seed was controlled by direct current modulation. The hybrid DPSSL generates 1064 nm laser pulses with an average power of 40W, a pulse duration of 20-40ns, and a repetition rate of 100-500kHz.

• 대한전자공학회논문지
• /
• 제27권4호
• /
• pp.598-603
• /
• 1990

This study evaluates the performance of an optical receiver for binary phase shift keying (BPSK) signals in the presence of short noise originating from the photo diode and phase noise of the optical source. The case of using I.O. hybrid compare with the fiber optic hybrid to mix received optical signal and laser local oscillator signal. The impact of these noise is minimized if loop natural frequency and power split ratio between data and carrier recovery branch are choosen optimally. Then it is obtained that required laser linewidt to achieve a BER of 10**-9. The results are the same except theat in case of using the fiber optic hybrid the required optical power is twice as much as the I.O. hybrid.

• 한국레이저가공학회:학술대회논문집
• /
• 한국레이저가공학회 2005년도 춘계학술발표대회 논문집
• /
• pp.48-52
• /
• 2005

• 해양환경안전학회:학술대회논문집
• /
• 해양환경안전학회 2018년도 공동국제학술발표회
• /
• pp.166-166
• /
• 2018

• 대한용접접합학회:학술대회논문집
• /
• 대한용접접합학회 2008년도 춘계학술발표대회 개요집
• /
• pp.48-48
• /
• 2008