• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2015.07a
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• pp.109-110
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• 2015

강재 부표는 구조적 강도가 우수하고 철재의 절단, 용접 등의 간단한 가공으로 원하는 모양을 쉽게 만들 수 있는 장점은 있으나, 소재의 특성상 해수에 의한 부식과 흘러나오는 페인트로 인한 환경오염, 무거운 중량, 이에 따른 설치 비용과 유지보수 비용의 증가 등 여러 가지 극복하기 힘든 문제점과 한계점을 가지고 있다. 이 연구에서는 우리나라 표준형 부표의 기본 소재로 사용하고 있는 강재 대신 친환경적인 경량재질의 소재를 이용한 부표를 모듈 구조로 설계함으로써, 기존 강재 부표의 문제점과 한계점을 뛰어넘어 효율적인 유지관리와 운영이 가능하고, 해양환경 오염의 방지와 경량화를 실현시킬 수 있는 표체 개선 방안을 제시하고자 한다. 또한, 경량 재질을 이용한 부표의 안정성과 경제성 검토를 통해, 기존 강재 부표와 비교함으로써 안정성과 경제성을 평가하고자 한다.

• Journal of Korean Ophthalmic Optics Society
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• v.21 no.2
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• pp.109-117
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• 2016

Purpose: The study was aimed to figure out the effect of materials and pigmentation of soft contact lens on the adherence of Staphylococcus aureus upon soft contact lenses deposited with tear components. Methods: The number of adherent S. aureus on clear and circle soft contact lenses made of etafilcon A, hilafilcon B, nelfilcon A was measured before and after incubation in artificial tear. Furthermore, the denaturalization level of tear protein with time after incubation in artificial tear was estimated by electrophoresis. Results: The adherence of S. aureus was significantly different according to the lens materials. The pattern of bacterial adherence on clear and circle contact lenses was different. That is, the adherent amount of S. aureus was somewhat larger on circle lens made of etafilcon A however, amount on circle lenses made of hilafilcon B and nelfilcon A was 89.3% and 71.3% of the number on clear lenses. When the tear protein was deposited on contact lenses, the number of adherent bacteria decreased and its degree was varied according to the lens material. The degree of decrease was the biggest in clear soft lens made of etafilcon A. Anti-bacterial effect of tear protein decreased with time after deposition of tear protein on soft contact lens and the amount of lysozyme also decreased. The reduction of anti-bacterial effect and quantity of lysozyme was different according to contact lens materials and pigmentation. Conclusions: It was revealed that the adherence of S. aureus depends on contact lens materials and pigmentation, and the specification of lens material affects more on adherence of S.aureus than pigmentation. It was further figured out the denaturalization level of anti-bacterial protein on soft contact lens varies according to lens materials and pigmentation, which produces an effect on the quantity of bacterial adherence.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2012.10a
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• pp.1000-1002
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• 2012

The material with superior biocompatibility and physical-chemical stability is required to fabricate high sensitive biosensors. Many kinds of biomaterials have been evaluated to apply for bioindustry. Recently, carbon based diamond and graphene thin films have been focal pointed as bio applications and their possibility is partially evaluated. Diamond thin film has many advantages for electrochemical and biological applications, such as wide potential window (3.0~3.5V), low background current and chemical-physical stability. And graphene film has many advantages as biomaterial, chemical-physical stability and conductivity. In this work, we have cultured human nerve cell (SH-SY5Y) on the nanocrystalline diamond, mirocrystalline diamond, graphene film and cell culture dish. We use MTT assay to evaluate the characteristics of cell culture on the substrates. As a result, nerve cell is well cultured on the carbon based diamond and graphene films as similar as cell culture dish. We expect that carbon materials have been applied for bioindustry such as biosensors.

• The Proceeding of the Korean Institute of Electromagnetic Engineering and Science
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• v.20 no.2
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• pp.59-67
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• 2009

본고를 통해 초고주파 이론과 공학 분야는 물론 물리학, 재료공학의 기초 학문 분야에서도 지대한 관심을 모으고 있는 Metamaterial(MTM) 구조에 대해 조명하고자 한다. 먼저 MTM의 핵심이라고 할 수 있는 Left-Handedness(LH) 왼손 전파 법칙과 LH 발생 재질인 Double Negative(DNG) 재질에서의 전파 특성을 상대 유전율과 상대 투자율 평면에서 확인하고, 일반 매질인 Double Positive(DPS)형인 오른손 전파 법칙 Right-Handedness(=RH) 매질과의 결합(Composite Right-and Left-Hnaded=CRLH)에서 얻어지는 특징들을 살펴본다. 특히 DPS와 DNC의 결합에서 얻을 수 있는 음의 공진과 0차 공진(Zero-Order Resonance)을 언급하고 ZOR을 응용한 RF 부품의 소형화와 특성 개선사례를 소개한다. 또한, 안테나와 전자파 산란 특성에 MTM의 특수한 성질을 이용하여, 크기를 줄이거나 표면파를 억제하거나 혹은 방사 개구를 확대 또는 렌즈 특성을 얻어낸 사례도 언급된다 그리고 LH 특성은 아니지만 MTM 계열인 ENG(Epsilon Negative), MNG(Mu Negative), ENZ(Epsilon Near Zero)를 응용한 예들을 보이고, MTM 관점에서 FSS(Frequency Selective Surface )의 특성을 논의하고, 그간에 발표된 대표적 MTM 연구 결과에 대한 소개를 마치고자 한다.

• The monthly packaging world
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• s.29
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• pp.54-55
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• 1995

• Journal of the Korean Wood Science and Technology
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• v.43 no.6
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• pp.714-720
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• 2015

Since physical and mechanical properties of wood are affected by environmental factors such as soil and climate change, this study investigated relationships between wood quality factors and stand characteristics of Castanopsis cuspidata var. sieboldii forest in the southern region of Korea, including Jeollanam-do Province and Je-ju island. The obtained results found very close relationships between physical and mechanical properties of wood and stand characteristics. The air-dried density and strength performance of woods showed a negative correlation with the diameter at breast height (DBH) while they were positively related to altitude and drainage of the forest site. And wood properties showed variations depending on the region. These results brought a conclusion that wood of Castanopsis cuspidata var. sieboldii in the southern region could be useful forest resources for timber production.

• Journal of the Korean Recycled Construction Resources Institute
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• v.9 no.3
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• pp.253-259
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• 2021

Plastic wastes generated from household waste are separated by mixed discharge with foreign substances, and recycling is relatively low. In this study, the effect of the ratio and content of mixed plastic waste coarse aggregate(MPWCA)s and mixed plastic waste fine aggregate(MPWFA)s filled with blast furnace slag fine powder on the slump and compressive strength of concrete was evaluated experimentally. The MPWCAs were found to have a similar fineness modulus, but have a single particle size distribution with a smaller particle size compared to coarse aggregates. However, the MPWFAs were found to have a single particle size distribution with a larger fineness modulus and particle size compared to fine aggregates. Meanwhile, the effect of improving the density and filling pores by the blast furnace slag fine power was found to be greater in the MPWFA compared to the MPWCA. As the amount of the mixed plastic waste aggregate(MPWA)s increased, the slump and compressive strength of concrete decreased. In particular, the lower the slump and compressive strength of concrete was found to decrease the greater the amount of MPWFA than MPWCA when the amount of MPWA was the same. This is because of the entrapped air and voids formed under the angular- and ROD-shaped aggregates among the MPWFAs. On the other hand, the addition of the admixture and the increase in the unit amount of cement were found to be effective in improving the compressive strength of the concrete with MPWAs.

• Journal of Sensor Science and Technology
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• v.9 no.6
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• pp.440-447
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• 2000

This paper describes a practical system to classify material temperature responses by composition of curve fitting and neuro-fuzzy inference. There are problems with a classification system which utilizes temperature responses. It requires too much time to approach the steady state of temperature response and it has to be filtered to remove the noise which occurs in experiments. Thus, this paper proposes a practical method using curve fitting only for transient state to remove the above problems of time and noise. Using the neuro-fuzzy system, the thermal conductivity of the material can be inferred on various ambient temperatures. So the material can be classified via its inferred thermal conductivity. To realize the system, we designed a contact sensor which has a similar structure with human finger, implemented a hardware system, and developed a classification software of curve fitting and neuro-fuzzy algorithm.

• Journal of the Korean Society of Radiology
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• v.11 no.4
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• pp.197-203
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• 2017

This study purpose is propose the basic data for selecting the optimal target material by analyzing the photon characteristics of various materials which was located in the head of medical linear accelerator. In this study, energy spectrum of 6, 15 MV photon beams were compared and analyzed for 13 target materials using MCNPX of Monte Carlo method. The mean energy for the 6 MV energy spectrum was 1.69 ~ 1.84 MeV and that for the 15 MV was 3.38 ~ 3.56 MeV, according to the target material. The flux for the 6 MV energy spectrum was $1.64{\times}10^{-5}{\sim}1.80{\times}10^{-5}{\sharp}/cm^2/e$ and that for the 15 MV was $1.76{\times}10^{-4}{\sim}1.85{\times}10^{-4}{\sharp}/cm^2/e$. The analysis shows that the average energy and flux increase with higher atomic number of the target material. Based on this study, it is possible to present the basic data about the physical characteristics of the photon, and it will be possible to select the target later considering economic, efficiency and physical aspect.

• Proceedings of the KIEE Conference
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• 2002.11b
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• pp.224-225
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• 2002

초고압 지중선로를 연결하는 접속함의 절연재료는 최근 에폭시에서 고무재질로 변화되고 있는 추세이다. 본 논문에서는 접속재용 고무절연재료를 선정하기 위한 전기적, 기계적인 방법을 소개하였고, 전기적 절연특성과 접착특성간에 상관관계가 있는지에 대하여 고찰하였다. 특히 실제 제품의 절연-반도전간 interface특성을 모의할 수 있는 특수형태의 매입형 전극을 설계, 제조 및 시험후 동일시료에서 접착특성 확인용 시편을 채취 및 실험함으로써 전기적특성과 기계적특성간의 직접적인 상관관계를 규명할 수 있었다. 또한 실험을 통해서 초고압 지중선로용 접속함을 위한 최적의 고무재질 선정이 가능하였다.