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레이저 최대 허용 노출에서의 피부 온도 상승에 관한 연구
신성선 ( Seong Seon Shin ),김재영 ( Jae Young Kim ),장경민 ( Kyung Min Jang ),백준혁 ( Joon Hyuck Baek ),양승진 ( Seung Jin Yang ),박종락 ( Jong Rak Park ) 조선대학교 공학기술연구원 2015 공학기술논문지 Vol.8 No.2
Simulations of the absorption of laser pulses and the temperature rise in human tissues were executed for long (pulse width: 100 ms, beam diameter: 0.61 mm) and short (pulse width: 5 ns, beam diameter: 0.33 mm) pulse conditions at 532-nm, 809-nm, 905-nm, and 1064-nm wavelengths. Correlations between maximum temperature rise and maximum permissible exposure recommended by laser safety standards were investigated and discussed in terms of the correction factor CA defined in the laser safety standards.
레이저 스팟 사이즈 및 공정 변수에 따른 금속분말(SUS316L) 적층 단면 특성 분석
신성선(SeongSeon Shin),이종훈(JongHoon Lee),김성욱(SungWook Kim),황준호(JunHo Hwang),김현덕(HyunDeok Kim) 대한용접·접합학회 2019 대한용접·접합학회지 Vol.37 No.5
This study looks into the significant effects of laser beam spot size in the directed energy deposition of SUS316L stainless steel, to determine optimal conditions. In the paper, the beam spot size was varied and measured by adjusting the vertical displacement of the focal point. The experimental test results, specifically optical microscope images, showed that the cross-sectional view of the deposited layer was clearly different when the focal length was changed. Also, the paper investigates the effect of other process parameters such as laser power output, powder feeding rate and gas feeding rate on the directed energy deposition process. An experimental test showed that feeding powder loss was increased when the gas feeding rate and powder feeding rate were increased. This paper also includes experimental test results showing that the dilution ratio and heat-affected zone rely on the laser power outputs.
신성선 ( Seong Seon Shin ),박종락 ( Jong Rak Park ) 조선대학교 공학기술연구원 2015 공학기술논문지 Vol.8 No.1
The optical constants and anatomical structures of human tissues were investigated. Based on the results of these investigations, simulations of the absorption of a laser beam in the tissue were performed using a numerical technique based on the Monte Carlo method in the wavelength range 370 nm-1570 nm. The absorbed power density exhibited larger values at wavelengths around 400 nm and 1450 nm and has been found to be determined mainly by the absorption coefficient of the tissue. The penetration depth was maximum at wavelengths around 1300 nm. The results of this study provide important information for the further study on the efficient laser stimulation in human tissues.
고속도공구강 소재를 이용한 DED 방식의 3D 프린팅 적층 최적화 연구
권용재,신성선,주상은,이종훈,황준호,김현덕 대한용접접합학회 2023 대한용접·접합학회지 Vol.41 No.3
In this study, an additive manufacturing (AM) optimization process experiment was conducted using high-hardness metal powders (AISI M4) that can be used for mold repairs. The process variables applied in the experiment were the laser power, laser head moving speed, and powder feed rate, and the manufacture cross section was analyzed through one-pass manufacturing. The AM efficiency was evaluated for each process with respect to the layer height, dilution ratio, and global energy density. In the case of the layer height, the AM efficiency was good under the condition of the laser output of 500 W. In the case of the dilution ratio, the AM efficiency was good under the conditions of a powder feed rate of 6 g/min and laser head moving speed of 500 mm/min. Finally, the GED values of the process variables applied in this experiment were calculated, and the AM efficiency was excellent at values between 60 and 108 J/mm2.