• 한국재료학회지
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• 제19권11호
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• pp.569-575
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• 2009

In this study, the effects of silver treatment and activation on the physical and chemical properties of spherical activated carbon (SAC) were studied. The textural properties of SAC were characterized by BET surface area, XRD, SEM, iodine adsorption, strength intensity, pressure drop and antibacterial effects. BET surface areas of SACs decreased with an increase of the amount of PR before and after activation, and the BET surface areas of SACs were found to be about 2-3 times the size of those before activation. The XRD patterns showed their existing state as stable Ag crystals and carbon structure. The Ag particles are seaweedlike and uniform, being approximately 5-10 μm in size deposited on the surface of activated carbon. All of the samples had much more iodine adsorption capability after activation than before activation. The strength values of SACs increased with an increase of the amount of PR, and there was a smaller drop in the strength values of SACs with silver treatment than with non-silver treatment after activation. The Ag-SAC composites showed strong antibacterial activity against Escherichia coli (E. Coli).

• 한국재료학회지
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• 제26권9호
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• pp.460-467
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• 2016

Activated carbons (ACs) have been used as EDLC (electric double-layer capacitor) electrode materials due to their high specific area, stability, and ecological advantages. In order to prepare ACs with high density and crystallinity, coal tar pitch (CTP) was activated by $K_2CO_3$ and the textural and electrochemical properties of the obtained ACs were investigated. Although the CTP ACs formed by $K_2CO_3$ activation had much smaller specific surface area and pore volume than did the CTP ACs formed by KOH activation, their volumetric specific capacitance (F/cc) levels as electrode materials for EDLC were comparable due to their higher density and micro-crystallinity. Structural characterization and EDLC-electrode performance were studied with different activation conditions of $CTP/K_2CO_3$ ratio, activation temperature, and activation period.

• Biomolecules & Therapeutics
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• 제32권3호
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• pp.309-318
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• 2024

Compared to other organs, the brain has limited antioxidant defenses. In particular, the hippocampus is the central region for learning and memory and is highly susceptible to oxidative stress. Glial cells are the most abundant cells in the brain, and sustained glial cell activation is critical to the neuroinflammation that aggravates neuropathology and neurotoxicity. Therefore, regulating glial cell activation is a promising neurotherapeutic treatment. Quinic acid (QA) and its derivatives possess anti-oxidant and anti-inflammatory properties. Although previous studies have evidenced QA's benefit on the brain, in vivo and in vitro analyses of its anti-oxidant and anti-inflammatory properties in glial cells have yet to be established. This study investigated QA's rescue effect in lipopolysaccharide (LPS)-induced behavior impairment. Orally administering QA restored social impairment and LPS-induced spatial and fear memory. In addition, QA inhibited proinflammatory mediator, oxidative stress marker, and mitogen-activated protein kinase (MAPK) activation in the LPS-injected hippocampus. QA inhibited nitrite release and extracellular signal-regulated kinase (ERK) phosphorylation in LPS-stimulated astrocytes. Collectively, QA restored impaired neuroinflammation-induced behavior by regulating proinflammatory mediator and ERK activation in astrocytes, demonstrating its potential as a therapeutic agent for neuroinflammation-induced brain disease treatments.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2003년도 학술.기술논문 발표회
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• pp.13-16
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• 2003

There is no study that application of the maturity using H.B.C and H.S.C. Also activation energy has different values according to the cement, admixture and water-cement ratio. Therefore to make accurate explanation for the effect of temperature on concrete strength development properties, it is necessary that activation energy value according to the kind of cement is reviewed. This study compares and estimates equivalent age using activation energy value obtained by this experiment and Freiesleben activation energy value with compressive strength of concrete. As the result of this study, activation energy value obtained by this study has more accurate explanation of temperature's influence on concrete strength development than Freiesleben activation energy value.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2003년도 학술.기술논문발표회
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• pp.13.1-16
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• 2003

There is no study that application of the maturity using H.S.C and H.S.C. Also activation energy has different values according to the cement, admixture and water-cement ratio. Therefore to make accurate explanation for the effect of temperature on concrete strength development properties, it is necessary that activation energy value according to the kind of cement is reviewed. This study compares and estimates equivalent age using activation energy value obtained by this experiment and Freiesleben activation energy value with compressive strength of concrete. As the result of this study, activation energy value obtained by this study has more accurate explanation of temperature's influence on concrete strength development than Freiesleben activation energy value.

• 한국건설순환자원학회논문집
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• 제5권3호
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• pp.223-229
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• 2017

원전 구조물에 주로 사용되는 중량 콘크리트의 경우 중성자에 오랜 시간 노출되면 콘크리트 자체가 방사선을 방출하는 방사화가 발생하게 된다. 이러한 경우 원전 구조물 해체시 많은 양의 방사성 폐기물이 발생되고 이를 처리하기 위한 비용이 큰 폭으로 증가하게 된다. 따라서, 본 연구에서는 원전 해체시 폐기물의 처리비용을 저감하기 위하여 방사화에 밀접한 관련이 있는 Eu 및 Co를 포함하고 있는 시멘트를 대상으로 저방사화 시멘트를 제작하였다. 또한, 저방사화 시멘트 개발을 위하여 원재료 수급부터 제조방법을 제안하였으며 이를 일반 시멘트 및 저발열 시멘트와 비교 분석하였다. 방사화 분석 결과 Eu는 검출되지 않았으며, Co는 3.75ppm으로 보통포틀랜드 시멘트보다 낮게 측정되었으며, 물리적 화학적 특성 역시 1종 보통포틀랜드 시멘트와 4종 저발열 포틀랜드 시멘트 기준에 부합하는 것으로 나타났다.

• 한국해양공학회:학술대회논문집
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• 한국해양공학회 2003년도 추계학술대회 논문집
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• pp.146-151
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• 2003

Reduced Activation Ferritic/Martenstic (RAFs) are leading candidates for structural materials of D-T fusion reactor. One of The RAFs, JLF-1 (9Cr-2W-V, Ta) has been developed and proved to have good resistance against high-fluency neutrino irradiation and good phase stability. Recently, in order to clarify the strengthening mechanical at high temperature, a new scheme to improve high temperature mechanical properties is desired. Therefore, the creep properties and creep life prediction by Larson-Miller Parameter method for JLF-1 to be used for fusion reactor materials or other high temperature components were presented at the elevated temperatures of $500^{\circ}C$, $550^{\circ}C$, $600^{\circ}C$, $650^{\circ}C$ and $704^{\circ}C$. It was confirmed experimentally and quantitatively that a creep life predictive e벼ation at such various high temperatures was well derived by LMP.

• 한국해양공학회지
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• 제18권2호
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• pp.58-63
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• 2004

Reduced Activation Ferritic/Martensitic Steels (RAFs) are leading candidntes for structural materials of a D-T fusion reactor. One of the RAFs, JLF-l (9Cr-2W-V, Ta) has been developed and has shown to have good resistance against high-fluency neutrino irradiation and good phase stability. Recently, in order to clarify the strengthening mechanisms at high temperatures, a new scheme to improve high temperature mechanical properties is desired. Therefore, the test technique development of high temperature creep behaviors for this material is very important. In this paper, the creep properties and creep life prediction, using the Larson-Miler parameter method for JLF-l to be used for fusion reactor materials or other high temperature components, are presented at the elevated temperatures of 50$0^{\circ}C$, 55$0^{\circ}C$, $600^{\circ}C$, $650^{\circ}C$ and 704$^{\circ}C$. It was confirmed, experimentally and quantitatively, that a creep life predictive equation, at such various high temperatures, is well derived mr the LMP method.

• Nuclear Engineering and Technology
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• 제51권5호
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• pp.1365-1372
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• 2019

The effects of Y and Ti on the microstructure stability and tensile properties of the reduced activation ferritic/martensitic steel have been investigated. The addition of Y and Ti affected the prior austenite grain size due to the pinning of the inclusions. Ti addition of 0.008 wt% to the steel was intended to promote the precipitation of nano-sized carbides with a high resistance to coarsening. 8Ti14Y exhibited a higher yield strength and a lower DBTT than the other alloys due to the fine grain size and additional precipitation hardening by (Ti, Ta)-rich MX. After thermal exposure at $550^{\circ}C$ for 1500 h, yield strength was dropped significantly in exposed 0Ti13Y. On the contrary, a lower reduction of YS was observed in 8Ti14Y. The $M_{23}C_6$ in 0Ti13Y and 8Ti14Y and MX in 25Ti14Y and 39Ti15Y coarsened seriously during ageing, which could be responsible for the reduction of the tensile properties of alloys.

• Computers and Concrete
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• 제12권4호
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• pp.377-392
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• 2013

This paper investigates prediction models estimating the hydration properties of concrete, such as the compressive strength, the splitting tensile strength, the elastic modulus,and the autogenous shrinkage. A prediction model is suggested on the basis of an equation that is formulated to predict the compressive strength. Based on the assumption that the apparent activation energy is a characteristic property of concrete, a prediction model for the compressive strength is applied to hydration-related properties. The hydration properties predicted by the model are compared with experimental results, and it is concluded that the prediction model properly estimates the splitting tensile strength, elastic modulus, and autogenous shrinkage as well as the compressive strength of concrete.