http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
곽태양(Kwak, Tae Yang) 역사비평사 2014 역사비평 Vol.- No.107
From 1964 to 1973, President Park Chung Hee deployed 312,853 South Korean troops to support the American war in Vietnam. The defining features of contemporary Korea were most critically determined by the particular way that Park leveraged and exploited the war. There are three critical problems with this popular understanding: (1) Park had become over-dependent on the special wartime relationship with the United States which both facilitated his authoritarianism during the war and prompted him to turn to formal dictatorship at the end of the war; (2) Park’s primary goal was unification of the Korean peninsula through rapid escalation of South Korea’s military-industrial capacity while maintaining or even bolstering America’s security commitment to South Korea, but he alienated American leaders and provoked a peninsular arms race that deepened and hardened the division; (3) Lastly, Park’s uneven development model was designed primarily for speed and military-industrial capacity without consideration for long-term viability or economic aberration producing lasting social division and corruption.
Jinju Jang(장진주),Taeyang Kwak(곽태양),Young Chul Kim(김영철),Heung-Jae Chun(전흥재),Dohyung Lim(임도형) 대한기계학회 2021 대한기계학회 춘추학술대회 Vol.2021 No.11
With the introduction of additive manufacturing by selective laser melting, complex shape such as porous structure became to manufacturability. However, it is reported that the additively manufactured Ti-6Al-4V implant has low ductility due to the needle-shaped alpha prime martensitic microstructure, and can be increased through heat treatment. Therefore, this study was to confirm the effect of heat treatment through changes in the microstructure and mechanical strength of porous Ti-6Al-4V implants additively manufactured. In the case of the specimen, an irregular porous structure like bone was applied to the cervical cage. And heat treatment was performed at 650°C for 2 hours and at 800°C for 2 hours. The specimens were measured the change in microstructure with EBSD, and mechanical strength was evaluated according to ASTM F2077 standard. As a result, it was confirmed that alpha prime phase decomposition occurred and precipitation of the beta phase in the specimens heat treated at 650°C and 800°C for 2 hours. And it was confirmed that the particle size of the beta phase grew at 800°C compared to 650°C. In addition, it showed improved ductility compared to the decreased strength at 800°C. We confirmed that heat treatment at 800 °C for 2 hours on the additively manufactured porous cervical cage is a suitable condition to improve the microstructure characteristics and ductility.