• Composites Research
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• v.18 no.4
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• pp.27-34
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• 2005

Salt water spray and immersion tests were experimentally conducted for over 6 months to investigate the durability of glass fabric/phenolic composites under salt water environment. Mechanical properties such as tensile properties, flexural properties, and shear properties were evaluated and thermal analysis properties such as storage shear modulus, loss shear moduls, and tan 6 were obtained through a DMA. A change in chemical structures was analyzed through a FTIR. According to the results, mechanical properties and thermal analysis properties were sensitive to salt water environment and these properties began to degrade in increasing in exposure times. However, tensile and flexural moduli started to decrease and then slightly increase as increasing in exposure times due to plasticization and crosslinking in matrix as well as physical swelling in composites. Beyond a certain exposure times, these properties began to decrease as further increasing in exposure times. Also the shape and location of peaks in FTIR curves were insensitive to exposure times, but the intensity of peaks would be. finally we found that the durability of glass fabric/phenolic composites were affected on salt water immersion environment rather than salt water spray environment.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.39 no.9
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• pp.871-877
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• 2015

Deep-sea equipment such as underwater robots and unmanned submersible vehicles, include various machine components and sensors, and it is important that their reliabilities be tested before use in the fields. This is necessary because they are affected by complex extreme-environment conditions, such as high pressures, extreme temperatures, and tidal forces that are present in the deep sea. We require test equipment that can conduct empirical tests in conditions that mimic these complex oceanic environments. In this study, we propose specifications that should be met, and a design plan for the primary components, which should limit their use to a maximum water pressure of 2.0 MPa, water temperature of $5{\sim}60^{\circ}C$, and a maximum flow velocity of 2 m/s. in work-in type underwater combined environment test equipment and. We present test system development procedures to verify the reliability of products and systems used in deep-sea environments.

• Journal of the Korean GEO-environmental Society
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• v.2 no.1
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• pp.5-13
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• 2001

The purpose of this paper is to present the pressuremeter test result and analysis for Yulchon Combined Cycle Power Plant(CCPP) site. The CCPP site is old backfill area with the hillcut materials obtained from the borrow sources near the mountains. The geology of this area consists of 6-layers from the ground level such as hillcut material, dredged clay fill, silty sand, original marine clay, weathered rock, soft rock, etc.. The pressuremeter test has been carried out with three different probe, in size and membrane type for all layers except the clay layers. The cone penetration test has been also carried out to collaborate with the pressuremeter test in the hillcut material layer.

• Aerospace Engineering and Technology
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• v.6 no.1
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• pp.230-236
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• 2007

The quality control of composite structure includes inspection, testing and monitoring in all processes from receiving inspection to part fabrication. The purpose of these activities is to ensure that the design objectives are consistently achieved. The quality factors include material, receiving inspection, storage and shelf-life control, environmental control, testing, inspection and record control. This paper presents the process verification method using destructive test and quality control method in composite structure of aircraft. And it is believed that the destructive test will be basis to obtain a reliability of non-destructive test in complex composite structure and to ensure the design requirements in composite part.

• Composites Research
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• v.24 no.4
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• pp.48-54
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• 2011

The effect of moisture contents by salt water on the strength of composite single-lap bonded joints is investigated. The specimens were manufactured in an autoclave by secondary bonding and immersed in the 3.5% salt water of $71^{\circ}C$ for different durations to get various moisture contents; 0, 0.2, 0.5, 1.0, and 2.0%(saturation). A total of 80 joint specimens were tested for 5 different moisture contents and 2 temperature environments. Test results show that while the joint strengths after the saturation of moisture decrease compared to those of dry ones, the strengths of the pre-saturated joint up to 1.0% of moisture content increase in both room and elevated temperature conditions. It is also shown that the strengths of joints tested in elevated temperature are slightly higher than the strength in room temperature by 2-5% until the moisture content reaches 1 %. In contrast, the high temperature strength of the saturated joint is about 5% lower than the room temperature strength.

• Journal of Environmental Health Sciences
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• v.15 no.1
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• pp.1-9
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• 1989

환경인자가 인체의 발암에 크게 기여하며, 대기오염도 흡연인자와 더불어 폐암발생의 주요인자로 주목되고 있다. 발암성 시험은 mouse, rat 등의 소동물을 이용하는 in vivo 시험법이 원칙이나, 시간과 경비가 많이 소요되므로, in vitro 생물시험법이 현재 발암물질의 screening 수법으로 많이 이용되고 있다. 특히 B.N.Ames에 의해 개발된 Salmonella균 변이주를 이용하는 방법은, 간편성, 신속성에 뛰어나고, 정성적 또는 정량적으로 발암성과 매우 높은 상관관계를 보이고 있어 최근 10여년간에 걸쳐, 수많은 화학물질 또는 대기오염물질과 같은 복합오염물질의 변이원성 및 발암성의 screening test로서 널리 응용되어 왔다.

• Composites Research
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• v.21 no.4
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• pp.1-6
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• 2008

This paper explains fire safety tests of a hybrid composite train carbody with carbon/epoxy sandwich bodyshell and stainless steel underframe. In this study, a large scale mock-up was used to evaluate the fire safety of the composite train carbody. The test was conducted to the bare composite carbody mock-up without interior facilities and the fully equipped one. Tile fire propagation and temperature distribution of the carbon/epoxy bodyshell and the glass phenol interior panels was evaluated under the real fire accident scenario. The test scenario was based on the DaeGu subway fire accident. From the tests, both the surface temperature of the interiors and the composite bodyshell wore lower than tile ignition temperature. In addition, the fire spread along the surface of the interiors and bodyshell was not occurred.

• Journal of the Korean Society for Marine Environment & Energy
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• v.19 no.1
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• pp.7-17
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• 2016

The present study experimentally considers dynamic performance of large floating wave-offshore hybrid power generation platform in extreme conditions. In order to evaluate the motion performance of the large floating hybrid power generation platform, 1/50 scaled model was manufactured. A mooring line was also manufactured, and free-decay and static pull-out tests were carried out to check the mooring model. A mooring line table was introduced to satisfy the water depth, and environmental conditions were checked. Motion responses in regular waves were measured and complicated environmental conditions including wave, wind, and current were applied to see the dynamic performance in extreme/survival conditions. Maximum motion and acceleration were judged following the design criteria, and maximum offset and mooring tension were also checked based on the rule. The characteristics of hybrid power generation platform are discussed based on these data.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 2017.04a
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• pp.134-134
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• 2017

전북지역의 130여개 스마트온실 중에서 주요한 10여개의 주요 온실에 대한 온습도, 이산화탄소, 광센서 및 기타 센서의 사용실태에 대한 조사를 수해하였다(2016년 9월~12월). 온실의 선정은 온실의 종류(비닐/유리)와 복합제어기 종류(국산/외산)를 중심으로 조사하였다. 국내외 업체의 장단점, 스마트기기의 활용과 문제점, 클라우드 기반의 3세대 한국형 스마트온실의 적용기반에 대한 조사를 수행하였다. 융복합 제어기와 센서는 자체의 신뢰성 이외에 운용상의 알고리즘 차이에서 오는 문제로 인해 농가에서 측정결과에 대한 신뢰성이 낮고, 측정이 부정확하고 일일측정 데이터에 대한 활용이 어렵고, 설정 값을 사용자가 직접 계산하고 값들을 입력해주어야 한다는 단점에 대한 의견이 대부분이다. 외국 제품은 데이터 측정값의 활용이 용이하고 복합 환경 상황에 알맞게 자동 계산 시스템이 체계적으로 작동하여 제어에 반영되며 국내 업체 설정 값의 범위보다 세밀하게 설정이 가능하다는 장점이 있으나 설치비용이 국내대비 3~4배 높고 고장 시 A/S가 느린 편이며 영어로 구성된 복잡한 시스템이기 때문에 100% 활용하기 어렵다는 단점이 있다. 스마트기기 활용은 복합 환경제어를 하는 농가이면 국내 업체와 외국 업체 모두 활용하고 있으며 주로 스마트 폰으로 사용되고 전용 어플이 아닌 PC원격 제어 소프트웨어인 팀뷰어(Teamviewer)를 이용하여 복합제어기 PC를 직접 조작하여 사용한다. 클라우드 활용으로는 복합환경제어기 회사에서 작물별 제어 방법과 데이터 정보를 제공하지 않는 점에 대한 농가의 불편함이 많은 편으로 작물별 농사방법이 많고 지역별 농사방법이 다르기 때문에 조사한 전북지역의 농가 10곳 모두 클라우드를 사용하지 않는 것으로 조사되었다. 다양한 온실 및 생육환경에 따른 표준화된 운영의 문제점을 개선하여 스마트팜에서 중요한 역할을 수행하는 복합센서의 표준시험방법과 절차를 개발하여 관련산업의 발전에 응용할 필요성이 있으며 단순한 하드웨어의 표준화 또는 개선방향보다는 농가의경험과 누적된 토양,작물 등의 재배 생육정보를 이용한 작물생육모델과 온실모델의 일치를 통해 센서-생육환경예측-검증방법의 포준화가 필요한 것으로 사료된다.

• Composites Research
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• v.23 no.3
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• pp.37-42
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• 2010

The fiber material properties, elastic constant and strength, are the most important factors among the various material properties for the design of composite pressure vessel, because of it's dominant influence on the performance of composite pressure vessel. That is, the deformation and burst pressure of pressure vessel highly affected by the fiber material properties. Therefore, the establishment of test method for exact fiber material properties is a priority item to design a composite pressure vessel. However, the fiber material properties in filament wound pressure vessel is very sensitive on various processing variables (equipment, operator and environmental condition etc..) and size effect, so that it isn't possible to measure exact fiber material properties from existing test methods. The hydro-burst test with full scale pressure vessel is a best method to obtain fiber material properties, but it requires a enormous cost. Thus, this paper suggests a newly developed test method, hoop ring test, that is capable of pressure testing with ring specimens extracted from real composite pressure vessel. The fiber material properties from hoop ring test method showed good agreement with the results of hydro-burst test with full scale composite pressure vessels.