http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
趙相明(Sang-Myung Cho),堀川浩甫(Kohsuke Horikawa) 한국해양공학회 1988 韓國海洋工學會誌 Vol.2 No.2
In order to consider the concept of the 'fitness for purpose' in fatigue design of offshore structure, fracture mechanics is applied to evaluate initial or weld defects.<br/> Generally, linear elastic fracture mechanics has been applied to estimate initial fatigue crack propagation rate as well as long fatigue crack propagation rate. But, initial fatigue crack propagation rate in elasto-plastic notch field may not be characterized by application of stress intensity factor range △K, because plastic effect due to stress concentration of notch may contribute to initial crack propagation. Therefore, to introduce the plastic effect into fatigue crack driving force, in this studty, the evaluating method of J -integral range △J, was developed for initial fatigue cracks in elasto-plastic notch field. The interpolation function for J -integral by Willson was modified for application to notch field. In calculation of △J obtained from the modified J -integral, stress gradient and crack closure behavior in the notch field were considered.<br/> The initial crack propagation rates in the notch fields of mild steels and high tensile strength steels were correlated to △J. As the result, it was cleared that the present △J is applicable to characterize the fatigue crack propagation rates in both the elastic and elasto-plastic notch fields.
내마모판의 광폭 경화육성 용접비드 형성을 위한 트윈토치 CMAW 공정개발
조상명,김성덕,황규민,Cho, Sang-Myung,Kim, Sung-Deok,Hwang, Kyu-Min 대한용접접합학회 2008 대한용접·접합학회지 Vol.26 No.2
The wearplate with Cr-C has been used in condition of severe abrasion. Recently, the demand of wearplate made by hardfacing with Cr-C has increased in the world, but it is lack of supply and expensive due to low productivity. CMAW (Compound Metal Arc Welding) is very useful process of several welding methods to make wearplate. In this paper, twin torch CMAW to use twin torch at the same time was developed to improve productivity and to ensure quality of wear plate. When the distance between two touches was smaller than 30mm, arc blow was occurred. However when the distance was larger than 35mm, there was no arc blow any more. If the oscillation path of each torch was overlapped together, the melt through at the overlapped zone was occurred due to concentrated heat input in substrate. On the other hand, the turning point of each torch was open more than 5mm, separated bead was generated. Therefore twin torch CMAW which has adequate conditions was able to make wearplate having flatter surface at the bead connection than single torch.
조성주,이상명,박병진,Cho, Sungju,Lee, Sang-Myung,Park, Byung-Jin 한국벤처창업학회 2014 벤처창업연구 Vol.9 No.4
최근 한국경제의 화두가 되고 있는 창업활성화를 위해서 많은 논의와 정책이 이루어지고 있으나, 결국 창업활성화는 창업 기업의 성공률이 높지 않다는 문제가 해결되어야 한다. 특히, 창업초기의 높은 실패율을 낮출 수 있는지의 여부가 창업활성화의 성패를 좌우하는 중요한 요인이 될 것이다. 이에 본 연구에서는 창업 초기기업의 실패 최소화 전략으로서 매우 유용한 시각을 제공하지만 그간 국내 학계에서 체계적으로 연구되지 않은 '린 스타트업'을 살펴보고, 이를 바탕으로 창업기업의 활용방안을 모색해 보고자 하였다. 구체적으로 린 스타트업'의 기본 프레임워크와 핵심원칙에 대한 설명과 함께, 창업기업의 사업추진 단계별 린 스타트업 개념의 적용방법을 사례를 통해 알아보는 한편, 린 스타트업'을 적용하는데 있어서 고려해야 할 사항을 제시하였다. 본 연구는 창업가가 실행할 전략뿐만 아니라 창업 실습을 가르치는 교육자와 창업 기업에 대한 멘토링을 제공하는 전문가들에게 효과적인 프레임웍이 될 수 있도록 전체적인 프로세스를 종합적으로 살펴보았다는 데 의의가 있다. There has been lots of discussions and new policies to encourage people to start new businesses. However, they key issue such as how to raise the success rate of new start-ups still needs to be resolved. Many believe that the success of policies and discussions for promoting entrepreneurship in Korea highly depends on how to lower the risks with which early stage start-ups encounter. In this backdrop, this study aims at providing an emerging approaches in entrepreneurship, 'lean start-up', which can work as an effective method with which early stage entrepreneurs can minimize challenges they face. Even though lean start-up is a widely accepted concept among practitioners and recognized as a useful tool for entrepreneurship and education, but has not got deserved attention from the academic world. This paper offers basic framework and key principles of lean start-ups, furthermore, shows Korean cases of step-by-step application methods of its concepts. It also suggest key issues in adopting lean start-up strategy. This study has implications and contributions for entrepreneurs, educators and researchers through providing comprehensive perspectives on process of the lean start-up strategy.
아연도금강판에 대한 중첩펄스 MIG 용접에서의 파형제어와 기공 발생 특성
조상명,김기정,이병우,Cho Sang-Myung,Kim Ki-Jung,Lee Byung-Woo 대한용접접합학회 2005 대한용접·접합학회지 Vol.23 No.1
Recently, application of arc welding to galvanized carbon steel sheet is on the increasing Ould in the fields of automobile and construction industries. In arc welding process, zinc is evaporated in weld pool, even under the appropriate welding condition and produce blowhole and/or pit. Zinc gas cause instability of arc and increase spatter and fume. This research is purposed to minimize the heat-input and the formation of porosities in the welded joint of the galvanized carbon steel sheet using variable polarity AC wave pulse MIG welding system. An appropriate welding condition which showed low spatter and good bead appearance was acquired by applying the AC pulse MIG welding machine to DC duplicated MIG welding with the solid wire. When oxygen gas was added to shield gas of MIG welding for galvanized steel sheet, arc length was increased and arc stability was improved. In the AC duplicated welding, the loss of galvanized layer was decreased as the amount of heat-input was decreased when the EN ratio was increased under the condition that average welding current was evenly set.
열간단조 금형 육성용접부 내균열성 및 내열충격성 평가방법에 관한 연구
조상명,김성호,정연호,백승희,장종훈,박철규,우희철,정병호,Cho, Sang-Myung,Kim, Sung-Ho,Jung, Yun-Ho,Baek, Seung-Hui,Jang, Jong-Hun,Park, Chul-Gyu,Woo, Hee-Chul,Jung, Byong-Ho 대한용접접합학회 2010 대한용접·접합학회지 Vol.28 No.3
Hardfacing is one of the frequently applying method to increase surface hardness in hot forging die. Recently, hardfacing receives great attention due to it's repair availability and low cost. In hot forging die, crack resistance and thermal shock resistance have been considered as major properties, However there are few studies for the assessment of these properties. So, it is necessary to establish the assessment method for crack resistance and thermal shock resistance in hardfacing for hot forging die. In this study, flux cored arc welding was applied to make hardfacing welds. Three point bending test was carried out to assess hardfacing weld's crack resistance, and high temperature bending test using salt bath was developed for thermal shock resistance. Consequently, it was possible to assess crack resistance and thermal shock resistance of hardfacing welds for hot forging die quantitatively.