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천연 및 인공원료로부터 제조한 생체친화형 하이드록시아파타이트 세라믹스
이종국,고영화,이난희,Lee, Jong-Kook,Ko, Young-Hwa,Lee, Nan-Hee 한국재료학회 2012 한국재료학회지 Vol.22 No.6
Hydroxyapatite (HA) is well known as a biocompatible and bioactive material. HA has been practically applied as bone graft materials in a range of medical and dental fields. In this study, two types of dense hydroxyapatite ceramics were prepared from natural bones and synthetic materials. The biocompatibility of HA ceramics for supporting osteoblast cell growth and cytotoxicity using an in vitro MG-63 cell line model were respectively evaluated. Artificial hydroxyapatite shows relative density of 93% with 1-2 ${\mu}m$ after sintering, but a hydroxyapatite compact derived from bovine bone has low sintered density of 85% with a small content of MgO. Irrespective of the starting raw materials, both types of sintered hydroxyapatite displayed similar biocompatibility in the tests. FE-SEM observations showed that most MG-63 cells had a stellar shape and formed an intercellular matrix containing fibers on sintered HA. The cells were well attached and grown over the HA surface, indicating that there was no toxicity.
이종국,조철영,이도관 한국항공우주학회 2013 한국항공우주학회 학술발표회 논문집 Vol.2013 No.11
초음속으로 비행하는 미사일이 카나드를 작동시킬 경우, 카나드 후류는 미사일의 꼬리날개에 induced 롤링 모멘트를 발생시키기도 한다. Induced 롤링모멘트를 감소하기 위한 하나의 방법으로 미사일 몸체에 대하여 자유회전하는 꼬리날개를 갖는 방식을 사용하여 왔다. 본 연구에서는 카나드와 몸체, 그리고 자유회전 꼬리날개로 구성된 시험모형에서 자유회전 꼬리날개의 회전수, 회전방향, 그리고 회전멈춤현상에 대한 풍동시험 결과를 다루고 있다. 시험은 국방과학연구소의 1.2 m × 1.2 m 삼중음속 풍동에서 수행되었다. It is well known that a canard-controlled missile has the problem of induced rolling moments at supersonic Mach numbers. The flows passed around canards interacts with tail fins, thereby induced rolling moments can be generated on tail fins for some canard conditions. Induced rolling moments can be reduced by the use of configurations with free-to-roll tail fins. This paper deals with wind tunnel results of revolution per minute, direction of revolution, and roll-lock phenomenon for a model with free-to-roll tail fins. The wind tunnel tests were conducted at 1.2 m × 1.2 m trisonic wind tunnel of Agency for Defense Development.
이종국,채현희,박유진,서보관 사단법인 인문사회과학기술융합학회 2017 예술인문사회융합멀티미디어논문지 Vol.7 No.4
This study aims at improving the CWTI (Construction Work Temperature Index) to manage safely the construction workers in heat wave season, because it is more dangerous than normal place and environment by the extreme high temperature environment and many kinds of tough construction work. To make effective and specific indicator model considering construction work site, we reviewed the previous CWTI research performance and proposed more advanced CWTI model finally. By applying the model to actual case study, we could confirmed its availability rather than the WBGT or the previous CWTI model. Firstly, in order to upgrade the previous research, we considerably checked the validity of each elements of the previous CWTI. Secondly, we adjusted the formua of the previous CWTI by experimental research. Lastly, we suggested the advanced CWTI by research on case study of the real construction site based on second experiment in the heat wave season of 2016. 본 연구는 여름철 건설작업 현장에서 폭염 시에 발생할 수 있는 작업자의 온열질환에 의한 안전사고 예방을 위한 CWTI (Construction Work Temperature Index, 건설작업 온도지수, 이하 CWTI)를 개선하고 활용성 검토를 목표로 한다. 따라서 건설현장 특성을 고려한 실질적이고 구체적인 관리지표 모델을 만들기 위해 선행 연구인 CWTI의 프로토타입을 검토하여 개선된 CWTI모델을 제시하고, 실제 현장에 적용하여 활용성을 검토하도록 한다. 본 연구는 첫째, 기존 연구의 부족한 점을 개선하기 위해 CWTI의 각 요소별 적용방식의 적절성 여부를 검토하고, 미흡한 부분의 개선 필요사항을 도출하고, 둘째, 이를 바탕으로 CWTI를 실제 실험을 통하여 개선하며, 셋째, 2016년 실제 폭염기간 중 건설현장 적용실험을 통하여 개선된 CWTI 모델의 활용성을 확인한다. 이를 통하여 보다 현실적인 건설현장의 특성에 맞는 건설작업 온도지수의 대안을 제시하였다.
The Effect of Innovation Alliances on Radical New Product Development Performance
이종국,안지영 한국상품학회 2011 商品學硏究 Vol.29 No.3
With firms’ increasing use of alliances for new product innovations, alliance portfolio has become a primary unit of analysis in marketing, management, and other disciplines. In particular, the portfolios of innovation alliances intended for knowledge creation play a critical role in generating radical new products. A common practice in examining the alliance portfolio is to aggregate alliances initiated in the past regardless of when they were initiated. However, this practice is based on a questionable assumption that alliances in a firm’s alliance portfolio have the same value or relevance for particular outcomes. Building on the concept of dynamic capability, We examine the value of innovation alliances initiated at different times in a firm’s innovation alliance portfolio. The analysis of innovation alliances in the biotechnology and pharmaceutical industries shows that 1) the value of innovation alliances first appreciate and then depreciate over time for radical new product development performance, and 2) the common practice of aggregating individual alliances without appropriately considering their weight can result in underestimating the effect of the innovation alliance portfolio on radical new product development performance. This study suggests that future research on the alliance portfolio needs to take into account the relevance of alliances initiated at different times for particular outcomes.