• Title/Summary/Keyword: 복합학

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Prediction of Mechanical Property of Biomorphic Composites (Biomorphic C/SiC 복합재료의 기계적 물성 연구)

  • Jeong, Jae-Yeon;Woo, Kyeong-Sik;Lee, Dong-Ju;Hong, Soon-Hyung;Kim, Yun-Chul
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.40 no.8
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    • pp.670-677
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    • 2012
  • In this paper, mechanical property of biomorphic C/SiC composite was calculated by unit cell analysis. The microstructural arrangements of carbonized pine and radiata pine which were impregnated with silicon, were idealized as square and hexagonal arrays. Unit cell was then defined and equivalent elastic constants were calculated. A single and double unit cell structures were considered. The effect of void distribution was also studied by monte carlo simulation.

A Characteristics of Al Matrix Composites Prepared by Rheo-compocasting and Squeeze Casting (Rheo-compocasting과 Squeeze casting법에 의해 제조된 AI기 복합재료의특성)

  • Seo, Yeong-Sik
    • Korean Journal of Materials Research
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    • v.6 no.12
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    • pp.1199-1212
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    • 1996
  • 본 연구는 주조성, 내압성, 내열성 등이 우수하여 군용 및 민수용 기계소재로 이용되고 있는 AI-Si-Mg계 AC4C 합금에 세라믹(AI2O3, AI2O3-TiC)을 강화시키는 복합재료제조에 관한 기초연구의 일환으로 수행하였다. 연구내용은 세라믹 강화재의 젖음성을 높이기 위하여 수소환원법에 의한 AI2O3입자의 Ni 피복과 기존의 프리폰 제조방법보다 간단하고 경제적인 자전연소합성법에 의해 AI2O3-TiC 다공성 pellet을 제조하여, 이들 강화재와 AC4C 기지금속을 이용하여 고대-compocasting 및 squeeze casting법으로 복합재료를 제조하고 미세조직, 계면생성물, 기계적 성질, 내마멸성 등의 특성을 조사하였다. 고대-compocasting법에 의해 제조된 AI2O3Ni 입자 강화 복합재료에서 강화재들은 응집체로 존재하지 않고 비교적 균일하게 분산되었고 AI2O3-TiC 강화재를 이용하여 squeeze casting으로 가압주조 하므로써 기지금속과 강화재의 젖음성이 향상되었다.

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Study on the Durability of Fiber Reinforced Composites (섬유강화 복합재료의 내구성에 관한 연구)

  • Kim, Je-Heon;Mun, Chang-Gwon
    • Korean Journal of Materials Research
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    • v.7 no.5
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    • pp.434-443
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    • 1997
  • 유리섬유와 에폭시 수지와의 계면전단강도에 미치는 수분흡수, 섬유직경 및 섬유의표면상태 등의 영향을 검토하기 위해서 two fiber fragmentation 시험법을 사용하였다. 그리고 유리섬유/에폭시 수지의 일방향 복합재료에서 수분흡수가 복합재료의 기계적 성질에 미치는 영향에 대해서도 검토하였다. 그 결과, two fiber fragmentation시험에서 계면전단강도는 수분흡수량 및 섬유직경이 클수록 작게 나타났으며, sizing한 것이 desizing한 것보다 크게 나타났다. 또 수분흡습에 의해 감소되었던 계면전단강도는 건조에 의해서 처음의 값의 약 50-60%까지 회복됨을 나타내었다. 그리고 일방향 복합재료의 인장강도는 수분흡수량이 증가함에 따라 현저히 감소함을 보였다.

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A Model for Shortest Path Calculation on lntermodal Transportation Network (복합 교통망에서의 최적경로산정 모형개발)

  • 최기주;장원재
    • Journal of Korean Society of Transportation
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    • v.16 no.4
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    • pp.167-186
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    • 1998
  • 자동차보급의 대중화와 함께 버스, 전철 등 대중교통체계의 지속적인 서비스 확충으로 인해 다양한 교통망의 이용행태가 나타나고 있다. 즉, 승용차를 이용하다가 대중교통수단을 이용하는 경우가 발생하게 되고 이러한 환경에서, 기타 통행대안들(예를 들면 목적지, 수단, 경로 등)이 효율적으로 연계 선택되어질 수 있도록 지원하여 전체 교통체계의 이용효율을 높일 수 있는 방안들이 강구되도록 요구되어지고 있다. 본고는 이런 관점에서 복합교통망에서의 경로안내 체계의 구현을 위한 알고리즘개발과 평가를 주목적으로 한다. 즉, 복합교통망에서의 경로탐색모형과 이 모형에 적용가능한 경로탐색 알고리즘의 제시하고, 이를 위해 복합교통말의 한 축이 되는 대중교통망의 특징을 분석하고 대중교통망에서의 경로탐색알고리즘을 평가하였으며 이를 바탕으로 일반가로망과의 최단경로구축의 통합방안을 제시하였다. 알고리즘의 구현과정을 필요한 데이터의 구축과정과 함께 도시함으로서 모형과 알고리즘에 대한 평가와 함께 실제 구현시 필요한 제반 사항들도 검토하였으며, 장래의 연구과제를 아울러 제시하였다.

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Easy, Efficient Class II composite resin restoration technique (쉽고 효율적인 클래스 II 복합레진수복테크닉)

  • Lee, Changhoon
    • Journal of the Korean Academy of Esthetic Dentistry
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    • v.27 no.2
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    • pp.66-74
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    • 2018
  • Composite resin restoration on class II cavities is a challenging procedure since it is tough to replicate proper contact, the natural shape of the tooth, etc. Moreover, it is not familiar with the procedure and tools for this specific situation, neither. Nowadays the patients, however, request more and more composite restorations which are relatively quick and more esthetic. In this case report, the class II composite resin restoration procedure is illustrated step by step. Every step must be considered its final consequence thoroughly. In this approach, we can minimize the finishing procedure and save our effort and time.

저궤도 인공위성 탑재 보안모듈의 우주방사선 차폐 방안 연구

  • Yang-Chan Cho;Dong-yun Choi;Kyung-ryeung Min
    • Review of KIISC
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    • v.33 no.6
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    • pp.45-49
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    • 2023
  • 뉴스페이스 시대가 도래하고 양자컴퓨터로 기존 암호체계의 파훼가 수월해진 오늘날 인공위성의 보안모듈은 고성능의 상용 부품을 필요로 한다. 본 연구에서는 PE와 Al의 복합소재를 활용하여 내방사선 능력이 적은 상용 부품을 사용한 인공위성 탑재 보안모듈의 차폐 방안을 제시하였다. 기존의 Al 단일 소재로 제작된 차폐 하우징의 성능과 경제성을 개선하기 위해 PE와 Al의 복합소재를 연구하였다. 이를 위해 OMERE를 통해 저궤도 위성의 임무 환경을 분석하여 PE와 Al 복합소재의 우주방사선 차폐성능과 Al 단일 소재의 우주방사선 차폐성능을 PHITS와 SRIM을 이용하여 비교분석하였다. 연구 결과, PE와 Al의 복합소재를 활용한 차폐 하우징은 가볍고 경제적인 장점을 가지며, 성능도 크게 향상됨을 확인하였다. 이러한 연구 결과는 보안모듈에 한정되지 않고 위성 부품의 차폐에 새로운 가능성을 제시함으로써, 전반적인 우주산업 발전과 위성의 임무 수행 실패율 감소에 기여할 수 있다.

Development of educational vibration equipment with multiple function (교육용 복합 진동실험장치 개발)

  • Rim, Kyung-Hwa;Park, Geun-Yun;Ryu, Ho-Min;Choi, Woo-Cheol;Moon, Seong-Jun;Shin, Hye-Jung
    • The Journal of Korean Institute for Practical Engineering Education
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    • v.2 no.2
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    • pp.74-82
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    • 2010
  • As the basic knowledge during designing most moving mechanical structures, vibration engineering is a subject teaching the theory on vibration control and isolation, which also cultivating the ability of analyze variety of vibration problems. However, vibration engineering is more difficult to understand than other dynamics courses in mechanical field, so the development of educational equipments in order to help understanding physical theory of vibration is really necessary. So in this paper we could see the effect after doing simple experiment process using the educational vibration equipment with multiple function, students could easily understand physical theory of vibration. The educational vibration equipment with multiple function and its application range are introduced, which could performance four kinds of typical vibration phenomenon: vibration of multidegree of freedom system, vibration of beam, vibration of beam, and vibration of plate. Finally, assessments of response and improvement plan are proposed through a survey.

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Limitations of neurobiological approach convergent to neuropsychiatry: DCD and two visual systems theory (신경정신학에 융복합되는 신경생물학적 접근법의 한계점: 발달성 협응장애와 두 시각 이론에 관한 종설)

  • Lee, Young-Lim
    • Journal of Digital Convergence
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    • v.13 no.6
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    • pp.225-234
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    • 2015
  • Neurobiological approach helps to resolve the mind-body dualism and develop new assessment and treatment approaches in psychiatry. However, it could be a problem to place too much emphasis on certain aspects of neurobiology, specifically structural neuroanatomy, because of the complexity or comorbidity of neuropsychiatric disorders. Developmental Coordination Disorder (DCD), for instance, is generally related to problems in motor skills and this movement disability is often related to perception. One account, two visual systems theory, relied on functional distinction in brain; ventral stream is responsible for visual recognition, and dorsal stream is responsible for the guidance of actions. However, Studies are now showing that shape perception is relevant to visually guided action, such as reaching-to-grasp an object. In this article, I reviewed fundamental findings of two-visual system theory and suggested problems of visually guided action to consider what shape perception implies for the two visual systems. Questions raised highlight possible limitations of adopting a structural neuroanatomical approach to account for perception and action effects, and by extent related psychiatric conditions such as DCD. In conclusion, neurobiological approach converging to neuropsychiatry, while useful, would be limited if it focuses too much on anatomical distinction.

Survey and Improvement Scheme for Clinical Practice of Emergency Medical Technology Students in the Convergence Society (융복합 사회에서 응급구조(학)과 학생들의 임상실습 실태조사 및 개선방안)

  • Jung, Sang-Woo
    • Journal of Digital Convergence
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    • v.15 no.1
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    • pp.287-299
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    • 2017
  • This study aims to suggest the improvement plan for clinical practice after examining the reality and the situation of clinical practice of EMT students. Clinical practice is as important as right to a variety of job experience in the convergence society and heating up according to appearance of NCS. Subjects were 115 EMT students. Data were collected for Jun. 16-17(2016), and analyzed by SPSS v. 18.0. Sophomores, who experienced only ER have a negative view about their future job prospect. On the other hand, juniors, who experienced ER and 119 rescue team have not virtually changed the way they view their future job prospect, supposedly due to the halo effect of the 119 rescue team clinical practices. Both groups wish to have opportunities to experience diverse clinical practices. This study suggests that will help students have a positive view about their job prospects by providing clinical practice institutions and solve the problem of difficulty in getting jobs.

Research Trend Analysis of Digital Divide in South Korea (디지털 정보격차 관련 국내 연구 동향 분석)

  • Ko, Jeonghyeun;Kang, Woojin;Lee, Jongwook
    • Journal of Korean Library and Information Science Society
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    • v.52 no.4
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    • pp.179-203
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    • 2021
  • This study aims to grasp the key issues and the direction for digital divide research in South Korea. Based on the 488 KCI journal articles published between 2003 and 2020, the authors analyzed the changes in the number of articles per year and the subject areas of journals. Furthermore, the topic modelling and keyword network anlaysis were applied to identify the subjects of research. The main findings can be summarized as follows: first, there was a stable trend for a while after the number of articles had increased by the year of 2007, and then there has been a sharp increase since 2019. Second, digital divide research has been conducted from diverse fields including social science, multidiscipline, and engineering. Third, the six subject areas were identified which are 'digital divide among regions', 'digital divide among people with disabilities', 'technical environment of digital divide', 'divide from information use and its consequence', 'legal and institutional environments of digital divide', and 'digital divide of the elderly'. Finally, it was shown that the areas of 'divide from information use and its consequence' and 'technical environment of digital divide' have attracted attention recently.