• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2000년도 봄 학술발표회 논문집
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• pp.489-495
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• 2000

When microorganisms such as bacteria and fungi are injected into porous medium such as soils along with appropriate substrate and nutrients, biomass retained in the soil pore. Soil pore size and shape are varied from the initial condition as a result of biofilm formation, which make hydraulic conductivity reduced. In this research, hydraulic conductivity reduction was measured after microorganism are inoculated and cultured with synthetic substrates and nutrients. Biomass-soil mixture was evaluated its applicability to the field condition as an alternative liner material in landfill by measuring hydraulic conductivity change after repetitive freeze-thaw cycles.

• 한국재료학회:학술대회논문집
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• 한국재료학회 2007년도 추계학술발표대회 및
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• pp.26.2-26.2
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• 2007

• 대한환경공학회지
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• 제22권5호
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• pp.927-938
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• 2000

박테리아를 토양과 같은 다공성 매질에 주입시키고 적절한 기질과 영양분을 공급시키면 박테리아는 매질의 표면에 부착하여 성장한다. 그 결과 바이오필름이 생성되어 공극의 크기가 감소하여 매질의 투수계수가 감소되며, 오염물질을 분해시키는 생물학적 오염분해 능력을 갖게 된다. 본 연구는 투수계수가 비교적 큰 모래와 화강풍화토에 박테리아를 접종, 배양한 후 토양의 투수계수의 변화를 측정하였으며, 배양된 바이오필름의 화학물질에 대한 저항성 및 온도변화에 대한 내구성 실험을 통해 대용 차수재로의 가능성을 평가하였다. 또한 bio-barrier의 유기물질 분해능 및 bio-barrier의 두께에 따른 미생물의 생장도를 column test를 통하여 측정하여 bio-barrier 내에서의 기질의 이동 및 생분해와 박테리아 농도의 분포 변화간의 관계를 제시하였다.

• 청정기술
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• 제26권1호
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• pp.79-87
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• 2020

The bio-oil produced from the fast pyrolysis of lignocellulosic biomass contains a high amount of oxygenates, causing variation in the properties of bio-oil, such as instability, high acidity, and low heating value, reducing the quality of the bio-oil. Consequently, an upgrading process should be recommended ensuring that these bio-oils are widely used as fuel sources. Catalytic fast pyrolysis has attracted a great deal of attention as a promising method for producing upgraded bio-oil from biomass feedstock. In this study, the fast pyrolysis of tulip tree was performed in a bubbling fluidized-bed reactor under different reaction temperatures, with and without catalysts, to investigate the effects of pyrolysis temperature and catalysts on product yield and bio-oil quality. The system used silica sand, ferric oxides (Fe₂O₃ and Fe₃O₄), and H-ZSM-5 as the fluidized-bed material and nitrogen as the fluidizing medium. The liquid yield reached the highest value of 49.96 wt% at 450 ℃, using Fe₂O₃ catalyst, compared to 48.45 wt% for H-ZSM-5, 47.57 wt% for Fe₃O₄ and 49.03 wt% with sand. Catalysts rejected oxygen mostly as water and produced a lower amount of CO and CO₂, but a higher amount of H₂ and hydrocarbon gases. The catalytic fast pyrolysis showed a high ratio of H₂/CO than sand as a bed material.

• 한국기계가공학회지
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• 제14권1호
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• pp.70-77
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• 2015

This paper develops and evaluates a mechanical machining process which involves drilling on PVS material. According to the material, two treatment experiments were conducted, one involving drilling in a wet condition or using a lubricant and one involving drilling in a dry condition with no lubricant. Drilling in a dry condition showed better performance in terms of the cutting time than in the wet condition. Otherwise, the wet condition has several advantages. The lubricant influenced the burr diameter size and minimized the temperature on the surface of the work piece. During the wet condition drilling process, a smaller burr diameter size was noted as compared to the dry condition. The temperature showed a linear correlation with the drill bit size, where a least-square analysis provided an $R^2$valuewhichexceeded 0.95. The wet condition required more cutting time than the dry condition. In this condition, the water provides a lubrication effect. A thin layer between the cutting edges and the surface of the work piece is formed. The chip formation is affected by the drilling depth. The color on the tips of the chips was darker than in the initial condition. No correlation between the drilling depth and the bore roughness was noted, but the variation of the cutting speed or the RPM influenced the roughness of the bore. The optimum cutting speed ranged from 40 RPM to 45 RPM in the condition which provided the finest roughness surface.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2006년도 춘계 학술발표회 논문집(II)
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• pp.509-512
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• 2006

We have many environmental problems by the polluted materials as a results of mechanical development these days. So people want to use building products made from natural things and take a good effect for people from those bio products. We can instance electron wave shelding, far infrared ray and anion emission, and anti-bacterial property as the latest trend of the bio building material. So we had a experiment to investigate how much bio materials affect concrete when we use in the concrete with cement substitution. We tested slump, 7days compressive strength, and air contents for physical properties of bio concrete. The result is that bio concretes with four bio ingredients have proper values comparing with target values for slump and air content but lower compressive strength than plain concrete.

• Transactions on Electrical and Electronic Materials
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• 제13권4호
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• pp.165-170
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• 2012

One-dimensional, nanomaterial field effect transistors (FET) are promising sensors for bio-molecule detection applications. In this paper, we review fabrication and characteristics of 1-D nanomaterial FET type biosensors. Materials such as single wall carbon nanotubes, Si nanowires, metal oxide nanowires and nanotubes, and conducting polymer nanowires have been widely investigated for biosensors, because of their high sensitivity to bio-substances, with some capable of detecting a single biomolecule. In particular, we focus on three important aspects of biosensors: alignment of nanomaterials for biosensors, surface modification of the nanostructures, and electrical detection mechanism of the 1-D nanomaterial sensors.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2005년도 하계학술대회 논문집 Vol.6
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• pp.127-128
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• 2005

UV-curable pressure sensitive adhesives were prepared by blending acrylic copolymer, copolymerized with butyl acrylate (BA), acrylic acid (AA) and vinyl acetate (VAc) by solution polymerization, triethyl amine (TEA) and trimethylolpropane triacrylate (TMPTA). The PSAs were evaluated by peel strength with varying contents of TMPTA and UV dose, and also glass transition temperature($T_g$) of PSAs were measured. When exposed on UV irradiation, the PSAs showed the decreased peel strength and increased $T_g$. And following UV irradiation, the PSAs did not leave any residue on wafer after peel off PSA.

• Journal of the Korean Wood Science and Technology
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• 제46권2호
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• pp.189-201
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• 2018

Intumescent system is a highly effective flame retardant technology that takes advantage of the mechanism of foaming and carbonization. In order to materialize Intumescent system, it is necessary to use reinforcement material to improve the strength of the material. In this study, we used kenaf as a natural fiber to manufacture intumescent/EVA (ethylene vinyl acetate) composites to improve mechanical and flame retardant performance. Finally two materials with different particle shape are applied to one system. Therefore, the influence factors of the particles with different shapes on the composite material were analyzed based on the tensile test. For this purpose, we have used the tensile strength analysis model and confirmed that it can only act as a partial strength reinforcement due to weak binding force between the matrix and particles. In the combustion characteristics analysis using cone calorimeter and UL 94, the combustion characteristics were enhanced as the content of Intuemscent was increased. As the content of kenaf increased, combustion characteristics were strengthened and carbonization characteristics were weakened. Through the application of kenaf, it can be confirmed that elastic modulus improvement and combustion characteristics can be strengthened, which confirmed the possibility of development of environmentally friendly flame retardant materials.

• 한국전기전자재료학회논문지
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• 제27권3호
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• pp.156-161
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• 2014

We have investigated the optical properties of plamonic waveguide with tapered structure based on InP material for photonic integrated circuit(PIC). The proposed plasmonic waveguide is covered with the Ag thin film to generate the plasmonic wave on metallic interface. The optical characteristics of plasmonic waveguide were calculated using the three-dimensional finite-difference time-domain method. The plasmonic waveguide was fabricated with the lengths of 2 to $10{\mu}m$ and the widths of 400 to 700 nm, respectively. The plasmonic mode and optical loss were measured. The optimum plasmonic length is $10{\mu}m$ and widths are 600 and 700 nm in the fabricated waveguide. This plasmonic waveguide can be directly integrated with other conventional optical devices and can be essential building blocks of PIC.