• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2016.11a
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• pp.146-146
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• 2016

최근 국민 소득향상과 더불어, 여가시간 증가에 따라 해양레저에 대한 관심이 크게 높아지고 있으며, 그에 따라 레저용 선박 수요도 증가하고 있다. 기존 국내 소형 선박의 경우 FRP(fiber-reinforced plastic)재료로 선박을 건조해 왔다. 그러나 해양환경 규제 강화로 FRP 선박의 건조가 감소하고 있으며, 친환경 선박에 대한 필요성이 대두되고 있다. 따라서 FRP재료를 대체하는 선박용 재료로 친환경적이고 가벼운 소재인 알루미늄 합금 재료가 선박건조 분야에서 각광을 받고 있다. 특히 5000계열 Al-Mg 합금은 가공성과 용접성이 우수하여 주로 구조용으로 많이 사용되고 있으나 경량화에 따른 빠른 선속이 유체충격을 증가시켜 선체에 캐비테이션 손상을 일으킬 수 있다. Al-Mg 합금의 경우에 부식성이 대단히 큰 해양환경에서 부식과 캐비테이션 침식이 복합적으로 일어나면 손상이 빠르게 증가되는 경향을 나타내어 선박의 수명을 현저히 단축시켜 경제적인 손실을 초래한다. 따라서 본 연구에서는 해수 내에서 Al-Mg 합금의 캐비테이션 저항성을 향상시키기 위해 알루미늄 합금 표면에 내식성 뿐만 아니라 경도 및 내마모성 등의 기계적 특성이 우수한 산화피막을 형성시키는 양극산화 기술을 적용하고, 다양한 봉공처리(sealing)방법에 따른 캐비테이션 특성을 평가하였다. 캐비테이션 실험은 압전(piezoelectric) 효과를 이용한 진동발생 장치를 사용하여 $30{\mu}m$ 진폭으로 일정하게 유지하였으며, 시편과 혼 팁 사이의 간격은 1mm로 하였다. 캐비테이션 실험 후에는 시편을 초음파 세척하여 진공 건조기에서 24시간 이상 건조한 후 정밀저울로 무게를 측정하였으며, 표면 손상 형상을 분석하기 위해 주사전자현미경(SEM)과 3D현미경을 이용하여 관찰하였다.

• The monthly packaging world
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• s.206
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• pp.96-107
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• 2010

지식경제부가 2010 미래패키징신기술 정부포상 심사 결과를 발표했다. 미래피키징 신기술 정부포상은 국내 패키징(포장) 산업의 우수한 기술 및 국내 패키징 산업의 발전에 기여한 유공자를 발굴, 포상함으로써 관련 종사자의 사기진작 및 기술개발 의욕을 고취하고, 궁극적으로는 국내 제조업의 경쟁력 강화를 극대화하기 위해 마련됐다. 포상부문은 코리아스타상(일반부문, 학생부문), 유공자 표창(표창장)으로 구분하여 시상한다. 코리아스타상 일반부문은 패키징 완제품, 재료(플라스틱, 종이 판지, 금속, 유리, 목재, 복합소재), 친환경, 기계(설비) 및 관련부품, 인쇄(라벨링), 부자재, 생산 및 가공공정, 패키지 디자인 등의 분야에서 신기술 개발 또는 개선으로 수출신장, 매출 수익 증대 및 발명특허 획득을 통해 패키징 기술력 발전에 기여한 기업을 대상으로 하며 코리아스타상 학생부문은 패키징 디자인 관련분야 전공자로 패키징과 연관된 컨셉으로 제품에 적용 가능한 상품성, 창의성, 표현성, 친환경성, 지속가능성 등이 어우러진 독창적인 제품을 대상으로 한다. 또한 유공자 표창 부문은 패키징 관련 핵심 기술개발, 패키징산업발전 정책연구 및 패키징산업 육성 등에 기여한 개인을 대상으로 시상하게 된다. 본 고에서는 2010 미래패키징 신기술 정부 포상 수상작들에 대해 살펴보도록 한다.

• Journal of Digital Convergence
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• v.17 no.10
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• pp.427-432
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• 2019

The purpose of this study is to explore the characteristics of spatial expression in the works of Terunobu Fujimori, Japan's leading eco-friendly architect, in line with the contemporary background on environmental issues. As a method of research, we will select five representative multi-room spaces from the 1990s to the present and explore the characteristics of expression in the space through literature research. As a result of the analysis, we were actively using the strategy of using natural materials to finish the space and introduce plants into the building. Japan's strategy of borrowing traditional methods was to use them as a way of expressing space, a way of expressing fantasy and deviance. We expect that the demands of modern people seeking novelty in this era and the eco-friendly building plan of feasible alternatives can be presented as another methodology for spatial design.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.9
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• pp.5861-5869
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• 2014

Existing studies of building exterior materials have focused on the colors or textures of cladding, and in terms of a design planning approach, have focused on the use of the environment and equipment and fire safety topics from an engineering perspective. As a result, little research has been done on performance guidelines for exterior materials, specifically according to the building type. Research into eco-friendly cladding materials is also in the rudimentary stage in a practical sense. In this study, the use of exterior materials over the last ten years in domestic construction was analyzed. The usage status of building exterior materials was evaluated quantitatively by frequency analysis, and its environmental performance is proposed through complex (qualitative + quantitative) analysis. The average value of the exterior material type number used for all analyzed buildings was 2.59. Glass, metal, stone, resin, cement, wood, and clay were used in that order with regard to the usage status. The analysis found that five of the materials satisfied the high efficiency and eco-friendly grading in terms of the four characteristics of an eco-friendly exterior. A list of eight eco-friendly elements was also proposed. The eco-friendly elements and characteristics of the exterior materials were derived to provide basic guidelines for domestic construction companies and design offices.

• Journal of the Korean Society of Safety
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• v.21 no.1 s.73
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• pp.133-140
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• 2006

According to Tokyo protocol which suggests the prevention of global environmental pollution, Korean government establishes the standard of architectural materials emission consistency with best effort to decrease the environmental pollution. But many current architectural materials which are used for constructing and remodeling buildings are composed of a variety of chemicals. These include stimuli bad for the residents' health and safety and harmful discharged air polluting substances such as volatile organic compounds(TVOCs) and formaldehyde(HCHO) that in tern include a variety of carcinogen substances. These discharged substances are also researched into inducing 'sick building syndrome' which induces headache, dizziness, vomiting and concentration failure among residents. But the standard of architectural materials according to the Korean apartment provision is limited to emission factors: HCHO and TVOCs. So the aim of this study is to present a standard of functional material's emission consistency about TVOCs including glues and paints, and a certification grade for green building by instituting a materials standard for green building which has consideration for the residents' safety.

• Composites Research
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• v.35 no.6
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• pp.456-462
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• 2022

Since natural fibers are highly flammable, it is not easy to make them flame retardant. In this study, a liquid flame retardant based on phytic acid, APTES, and Thiourea, which are flame retardant candidates derived from nature, was prepared and its performance was verified through flame retardant treatment and flame retardancy evaluation of bamboo fibers. When a liquid flame retardant is used, it is possible to treat a large amount of natural fibers with flame retardant treatment. Nine types of flame-retardant treated bamboo fibers were prepared according to the Taguchi design of experiment method. Thereafter, vertical burning test and microcalorimeter test were performed for flame retardancy evaluation, and the surface of natural fibers before and after flame-retardant treatment was compared using scanning electron microscope. The results show that phytic acid has a significant effect on improving the flame retardancy of natural fibers. Through microstructure analysis, it was assumed that the phytic acid helps flame retardant to uniformly adhere to the surface of natural fibers. If such research results are utilized, it is possible to make a large amount of natural fibers high flammability in an eco-friendly way, which is expected to be advantageous for the application of prototypes.

• Composites Research
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• v.36 no.2
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• pp.126-131
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• 2023

Growing environmental concerns regarding pollution caused by conventional plastics have increased interest in biodegradable polymers as alternative materials. The purpose of this study is to develop a 100% biodegradable nanocomposite material by introducing organic nucleating agents into the biodegradable and thermoplastic resin, poly(lactic acid), to improve its properties. Accordingly, cellulose nanofibers, an eco-friendly material, were adopted as a substitute for inorganic nucleating agents. To achieve a uniform dispersion of cellulose nanofibers (CNFs) within PLA, the aqueous solution of nanofibers was lyophilized to maintain their fibrous shape. Then, they were subjected to primary mixing using a twin-screw extruder. Test specimens with double mixing were then produced by injection molding. Differential scanning calorimetry was employed to confirm the reinforced physical properties, and it was found that the addition of 1 wt% CNFs acted as a reinforcing material and nucleating agent, reducing the cold crystallization temperature by approximately 14℃ and increasing the degree of crystallization. This study provides an environmentally friendly alternative for developing plastic materials with enhanced properties, which can contribute to a sustainable future without consuming inorganic nucleating agents. It serves as a basis for developing 100% biodegradable green nanocomposites.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.46 no.1
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• pp.18-31
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• 2018

Rotorcrafts have more severe crashworthiness conditions than fixed wing aircraft owing to VTOL and hovering. Recently, with the increasing demand for highly efficient transportation system, application of composite materials to aircraft structures is increasing. However, due to the characteristics of composite materials that are susceptible to impact and crash, demand to prove the crashworthiness of composite structures is also increasing. The purpose of present study is to derive the structural concept of composite subfloor for rotorcrafts and verify it. In order to design a crashworthy composite subfloor, the conceptual design of the testbed helicopter for the demonstration and the derivation of energy absorbing requirement were carried out, and the composite energy absorber was designed and verified. Finally, the testbed for the demonstration of a crashworthy composite structure was fabricated, and performed free drop test. It was confirmed that the test results meet the criteria for ensuring occupant survivability.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.02a
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• pp.281-281
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• 2011

산업 환경에서 친환경 및 에너지효율성을 중요한 조건이 되면서 고효율성 및 다기능을 가진 재료에 대한 연구가 활발히 진행 되고 있다. 특히 Al-Ti-N 코팅은 이미 경도 측면에서 우수 하여 고속 공구 부품에 널리 사용되고 있고 최근에 Al-TiN에서 Si 첨가는 40GPa이상의 고경도와 1000도 이상의 산화온도를 지닌 나노 혼합물 코팅을 형성 시키는 것으로 알려져 있다. 본 연구에서 Al-Ti에 Si, Cu, Cr 을 첨가하였을 때 코팅을 형성하였을 때 바뀌는 물성 변화을 확인하였다. 이러한 연구를 위해 Al-Ti 합금 조성 중 가장 우수한 것으로 알려진 60:40으로 타겟을 만들어 스퍼터 장비를 이용해 코팅을 형성하여 기초 실험을 진행하였다. 그 근거로 하여 3원계인 Si, Cu, Cr 을 첨가하여 각각의 단일 타겟으로 만들고 코팅을 형성하였다. 타겟과 코팅의 성분이 동일한지 확인하기 위해 EPMA분석을 하였고 그 결과 오차 범위 내에 동일한 것으로 확인하였다. 또 내산화성 테스트를 위해 400도에서 1000도로 가열된 대기 중에 코팅 층을 1시간씩 노출시키는 공정을 통해 확인하였고 내식성 테스트는 SUS 304계열 위에 코팅을 하여 Potentiodynamic polarization scan 장비로 비교해 보았다. 표면경도는 3원계 코팅인 경우 질소비율이 증가할수록 30GPa ~ 35GPa까지 증가하였고 XRD 분석 결과와 비교 시 (111), (200) peak가 명확할수록 경도 값이 높은 것으로 확인하였다. 마모테스트 결과 3원계인 코팅 층이 dry상태에서 감소하는 경향을 보였다. 특히 0,26까지 감소한 Si 을 첨가한 코팅 층은 H/E지수도 좋아 마모트랙의 길이도 짧아 우수한 것으로 알 수 있었다. 이런 결과에서 보듯 3원소 이상 첨가 시 특성변화가 차이가 있다는 것을 알 수 있었다.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.67 no.12
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• pp.1633-1640
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• 2018

Epoxy resin is a polar thermosetting polymer that is widely employed in different branches of industry and everyday life, due to their stable physical and chemical properties. Of all the polymer materials currently being used in the electrical insulation industry, epoxy resin is the most widely used kind, chosen as the base polymer material in the present study. Composites were prepared according to the mixing ratio (MS: MA, 1: 9, 3: 7, 5: 5, 7: 3, 9: 1)of mixture for Heterogeneous Minerals(Micro Silica:MS, Micro Alumina:MA) (MS+MA). We have investigated for AC electrical insulation breakdown characteristics and the dielectric properties (permittivity, dielectric loss, and conductivity) with frequency changes. The electrical AC insulation breakdown performance was improved with the increase of the mixing ratio of MS according to heterogeneous mineral material mixture(MS+MA). As Dielectric properties, the dielectric constant and dielectric loss increased with decreasing frequency and decreased with increasing MS content ratio of heterogeneous mineral mixture. Tensile strength and flexural strength according to the mixing ratio (MS + MA) of epoxy / heterogeneous mineral mixture were studied by mechanical properties. The performance of mechanical tensile and flexural strength was significantly improved as the fill contents ratio of MS increased.