http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
내식성 향상을 위한 마그네슘합금의 ZrO<sub>2</sub> 적용 레이저 표면 처리
윤상우,강동찬,김주한,Yoon, Sangwoo,Kang, Dongchan,Kim, Joohan 한국기계가공학회 2016 한국기계가공학회지 Vol.15 No.4
The laser surface treatment of magnesium alloy was studied. $ZrO_2$ was used as sintering ceramics, and its corrosion resistance was verified. Appropriate laser parameters were proposed for homogeneous solidification of the sintered layer. The chemical compositions of the sintered layer were analyzed with laser-induced breakdown spectroscopy. $Na_2SO_4$ was used for a corrosion test, and the resistance of the sintered sample was confirmed. The microstructures of the sintered parts were also examined. The solidified grains on the top sintered surface were observed; however, reasonable fusion was obtained at the interface between the baseline and the ceramics. Laser surface treatment using $ZrO_2$ on magnesium alloy showed an improvement in corrosion resistance.
윤상우(Sangwoo Yoon),김주한(Joohan Kim) 한국생산제조학회 2015 한국생산제조학회지 Vol.24 No.4
A non-symmetric laser beam was used for cutting a thin glass substrate and its effect was investigated. In laser cutting of brittle materials, controlling crack initiation on the surface is crucial; however, it is difficult to ensure that crack propagation occurs according to a designed laser path. A lot of deviation in crack propagation, especially at the edge of the substrate, is usually observed. A non-symmetric laser beam generates a non-uniform energy distribution, which enhances directional crack propagation. A 20-W pulsed YAG laser was used for cutting a thin glass substrate. Parametric analysis was carried out and the crack control of the non-symmetric laser beam was improved. A theoretical model was presented and the limitations of the proposed process were also discussed.
Measurement of Substance Diffusion on a Bio-body Surface Using Laser Plasma Spectroscopy
Sangwoo Yoon(윤상우),Jiheon Oh(오지헌),Seongyong Park(박성용),Jaekyeong Jung(정재경),Joohan Kim(김주한) 한국기계가공학회 2019 한국기계가공학회지 Vol.18 No.7
The diffusion of the drug component of the inflammatory patch into the living tissue was analyzed by laser induced plasma spectroscopy (LIBS). Calcium element, which is a diffusion catalyst of the drug in the inflammatory analgesic patch, is transferred into the body through the diffusion process of the substance. The test pieces used in the experiment are pig skin tissues which are similar to human skin. As a result, the diffusion coefficient D of the calcium element was found to be average 8.24 × 10-2 (㎛²/s). Experimental results showed that the most influential factors on the diffusion of materials were temperature variables.
마그네슘 합금 표면의 지르코니아 분말 레이저 소결과정에서 조사 패턴이 접합 계면 품질에 미치는 영향
윤상우(Sangwoo Yoon),김주한(Joohan Kim) 한국기계가공학회 2021 한국기계가공학회지 Vol.20 No.2
The quality of the ceramic sintered coating on a metal surface through laser surface treatment is affected by the laser irradiation pattern. Depending on the laser irradiation pattern, the amount of residual stress and heat applied or accumulated on the surface increases or decreases, affecting the thickness attained in the ceramic sintering area. When the heat energy accumulated in the sintering area is high, the ceramic and the metal alloy melt and sufficiently mix to form a homogeneous and thick bonding interface. In this study, the thermal energy accumulation in the region sintered with zirconia was controlled using four types of laser processing patterns. The thickness of the diffusion region is analyzed by laser-induced breakdown spectroscopy of Mg–ZrO₂ generated by laser sintering zirconia powder on the magnesium alloy surface. On the basis of the analysis of the Mg and Zr present in the sintered region through LIBS, the effect of the irradiation pattern on the sintering quality is confirmed by comparing and analyzing the heat and mass transfer tendency of the diffusion layer and the degree of diffusion according to the irradiation pattern. The derived diffusion coefficients differed by up to 9.8 times for each laser scanning pattern.
내식성 향상을 위한 마그네슘합금의 ZrO₂ 적용 레이저 표면처리
윤상우(Sangwoo Yoon),강동찬(Dongchan Kang),김주한(Joohan Kim) 한국기계가공학회 2016 한국기계가공학회지 Vol.15 No.4
The laser surface treatment of magnesium alloy was studied. ZrO₂ was used as sintering ceramics, and its corrosion resistance was verified. Appropriate laser parameters were proposed for homogeneous solidification of the sintered layer. The chemical compositions of the sintered layer were analyzed with laser-induced breakdown spectroscopy. Na₂SO₄ was used for a corrosion test, and the resistance of the sintered sample was confirmed. The microstructures of the sintered parts were also examined. The solidified grains on the top sintered surface were observed; however, reasonable fusion was obtained at the interface between the baseline and the ceramics. Laser surface treatment using ZrO₂ on magnesium alloy showed an improvement in corrosion resistance.
레이저 플라즈마 분광 기법을 이용한 금속 마찰 표면에서 물질전달 측정
윤상우(Sangwoo Yoon),김지훈(Jihoon Kim),김주한(Joohan Kim) 한국기계가공학회 2017 한국기계가공학회지 Vol.16 No.4
We quantitatively measured the mass transfer from friction surfaces, specifically brake pads and rotors, using laser plasma spectroscopy. Specifically, we modelled the mass transfer from the pad to the rotor and measured the elemental diffusion intensity distribution in the rotor material using laser plasma spectroscopy. The main elements measured were Cu, Ni, Ti, and Cr, and the distribution of these after transfer was measured as the ratio of the atomic peak and the ion peak of the plasma in the rotor exposed to friction and the surface composition of the rotor and the roughness, respectively. We measured and quantified the diffusion coefficient for each element through the mass transfer model and found that Cr obtained the largest diffusion coefficient (D) of the elements measured based on this system with a value of 1.9484×10<SUP>-15 </SUP> m<SUP>2</SUP>/s.