http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
소결체의 Nd:YAG 레이저 용접 시 보호가스가 용접강도에 미치는 영향
김용(Y. Kim),양현석(H. S. Yang),박기영(K. Y. Park),이경돈(K. D. Lee) 한국레이저가공학회 2007 한국레이저가공학회 학술대회 논문집 Vol.2007 No.-
This study includes the effects of shielding gas types and flow rate on Nd:YAG Laser weldability of sintered material. The types of shielding gas were evaluated for He, Ar and N₂. Bending strength, porosity rate, hardness and D/W ratio testing of laser weld are carried out to evaluated the quality for fusion area. As a results, Ar gas was showed the best welding strength even the porosity rate is the most value, and increased the flow rate was also improvement the bending strength. Therefore we could know that bending strength is not only affect the porosity rate but also melting degree.
이경돈(K.D.Lee) 한국자동차공학회 1992 한국자동차공학회 춘 추계 학술대회 논문집 Vol.1992 No.11
Automotive plastic bumper systems are increasingly used because of weight reducion and styling in passenger cars. Also recent needs for recycling will necessitate a use of thermoplastics instead of thermosets and fiber-reinsforced plastics in bumper systems.<br/> In this study, some of domestic plastic bumper systems are investigated and classified into four types according to components, their performance, and materials used in each component. Among them, two types of front bumper systems are selected, which have an injection molded beam and a blow molded beam respectively and both of them are made of PBT/PC alloy. Their performance is comprehensively studied through center pendulum tests and finite element alalysis.
탄성 힌지 타입 레버 메커니즘을 이용한 자동 초점 조절 미세구동장치에 대한 연구
이재석(J. S. Lee),홍석인(S. I. Hong),김호상(H. S. Kim),장한기(H. K. Jang),이경돈(K. D. Lee) 한국정밀공학회 2006 한국정밀공학회 학술발표대회 논문집 Vol.2006 No.5월
In precision laser microfabrication, focusing is essential to acquire good machining precision and uniform machining quality. If it does not perform, laser machining cannot be realized. So, confocal scanning method with high depth resolution is used for focus detection technique. This paper is concerned with a procedure for design, analysis and performance test of an autofocus fine actuating stage, which is composed of flexure-hinge type lever mechanism and piezoelectric actuator. Through series of analytical design, the stage is simplified as a rigid bodies(lever and main body) and springs(flexure hinges). The simplified model was applied to determine the dimension of flexure hinges and lever. After structural analysis confirmed design requirement, an actual stage was made and verified through an experiment on the static and dynamic characteristics(maximum stroke and 1st natural frequency). The fabricated stage was satisfied with the design requirement.