http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
오수환,박문호 대한전자공학회 2003 電子工學會論文誌-SD (Semiconductor and devices) Vol.40 No.9
본 논문에서는 광의 결합 메커니즘이 다른 ITG(integrated-twin-guide) 와 BT(butt coupled) 구조를 가지는 두 종류의 파장 가변 DBR-LD의 제작공정과 성능에 대해서 기술하였다. 두 종류의 DBR-LD는 PBH(planar buried heterostructure) 구조론 가지며, MOVPE 성장으로 제작하였다. 제작된 DBR-LD 광출력 특성을 측정한 결과 BT-DBR-LD가 ITG-DBR-LD보다 임계전류 변화폭, 광출력 변화 폭, 기울기 효율에서 2배 이상의 우수한 특성을 나타내었다. 그리고, 준 연속 파장 가변 특성은 BT-DBR-LD가 7.2nm, ITG-DBR-LD가 7.4nm 이며, SMSR이 35dB 이상으로 우수하게 나타났다. 이와 같이 BT DBR-LD가 특성이 우수한 것은 BT 구조가 ITG 구조보다 높은 결합 효율을 나타내기 때문이다. In this paper, we described the fabrication and the performance of wavelength tunable distributed bragg reflector (DBR) laser diode (LD), having different waveguide coupling mechanisms; integrated-twin-guide (ITG) DBR-LD and butt coupled (BT) DBR-LD. This deviceis fabricated by metal organic vapor phase epitaxy (MOVPE) growth and planar buried heterostructure (PBH)-type transverse current confinement structure. The result of measurement, the optical performance of BT-DBR-LD is better over 2 times than that of ITG-DBR-LD at the variation of threshold current and output power, and slop efficiency due to the higher coupling efficiency of the butt coupled structure than the integrated twin guide structure. The maximum wavelength tuning range is about 7.2nm for ITG DBR-LD and 7.4nm for BT DBR-LD. Both types of lasers have a very high yield of single mode operation with a side-mode suppression ratio of more than 35dB.
오수환,조정우 대한토목학회 2023 KSCE Journal of Civil Engineering Vol.27 No.11
This study investigates the commonalities and differences in aviation occurrences among three Northeast Asian countries – South Korea, China and Japan, using the ICAO’s Integrated Safety Trend Analysis and Reporting System (iSTARS) dataset. Logistic regression and latent class analysis are employed to identify factors influencing the likelihood of fatalities and to classify occurrences into distinct groups. The findings indicate that operational issues in airspace pose greater risks than runway-related issues in this region. The ground and landing flight phases have lower fatality likelihoods compared to the cruise phase, and winter seasons show reduced odds of fatalities. Latent class analysis identifies five distinct occurrence classes, highlighting specific risks and areas for targeted interventions. Technical and environmental issues are prominent in Japan, while operational issues during the cruise and maneuvering phases are significant in South Korea, associated with a high fatality rate. Light recreational general aviation flights pose a considerable risk of fatalities in China and Japan. The findings of this study highlight the need for comprehensive research to explore the causes and contributing factors of aviation occurrences in different countries to enhance safety practices and mitigate fatality risks.