• 한국전기전자재료학회논문지
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• 제19권9호
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• pp.849-854
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• 2006

In this study, the hybrid electrodes, composed of the activated carbon powders and $LiCoO_{2}$ powders, were prepared as a cathode for the high-capacitance type hybrid capacitor, and the electrochemical properties of the hybrid electrodes were examined in terms of the weight composition and the milling time of $LiCoO_{2}$ powders. The specific volumetric capacities were increased with increasing of the composition of $LiCoO_{2}$ powders in the hybrid electrodes. On the other hand the coin cell capacitors, using the hybrid electrodes with $LiCoO_{2}$ poweders milled for 200 h, have exhibited the lower internal resistivities and the better capacity retention after 100 charge-discharge cycle than those of the coin cell capacitors using the hybrid electrodes with raw $LiCoO_{2}$ powders.

• 한국초전도ㆍ저온공학회논문지
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• 제13권1호
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• pp.51-55
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• 2011

In this study, the liquid-vapor (L-V) separator equipped with liquid-level meter is developed. In the developed L-V separator, the flange is designed to be attachable so that the separator can be flexibly applied under any cases where the volumetric of L-V separator is varied by the system requirement. The leak-tightness between the attachable flange and the chamber is experimentally confirmed with the use of double groove indium wire sealing even under the high pressure up to 20 bar. In addition, the liquid-level meter is designed and fabricated to figure out the inner state of L-V separator. It consists with 19 carbon composition resistors in series. All resistors are separately calibrated in the temperature range from 77 K to 200 K. The performance of the L-V separator and the liquid-level meter is investigated with experimental tests, and the result is presented in this paper.

• Advances in environmental research
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• 제6권4호
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• pp.255-264
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• 2017

This work investigated the use of sugarcane bagasse ash (SCBA) generated by an energy cogeneration process in sugarcane mill as an alternative raw material in soil-cement brick. The SCBA obtained from a sugarcane mill located in southeastern Brazil was characterized with respect to its chemical composition, organic matter content, X-ray diffraction, plasticity, and pozzolonic activity. Soil-cement bricks were prepared by pressing and curing. Later, they were tested to determine technical properties (e.g., volumetric shrinkage, apparent density, water absorption, and compressive strength), present crystalline phases, and microstructural evolution. It was found that the SCBA contains appreciable amounts of silica ($SiO_2$) and organic matter. The results showed that the SCBA could be used in soil-cement bricks, in the range up to 30 wt.%, as a partial replacement for Portland cement. These results suggest that the SCBA could be valorized for manufacturing low-cost soil-cement bricks.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2004년도 Proceedings of ISRS 2004
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• pp.57-59
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• 2004

This paper reports the observation of the interferometric synthetic aperture radar (InSAR) phase anomaly on a newly reclaimed mudflat, Hwaong, in west coast of Korea, detected by a series of Radarsat-l SAR data obtained mostly during 2003. The observed phase anomaly could be from subsidence of mud land caused by volumetric contraction of mud in dry season. This process must have been initiated from March 2002 when tidal water supply to this region was permanently blocked by the newly constructed embankment. The maximum subsidence rate measured from InSAR signal is about 3 cm per month. The local heterogeneity of the subsidence rate over the reclaimed mudflat may indicate various mud composition, surface-subsurface hydrological processes, or subsurface information of the mud and basement rock structure. In-situ measurement must follow to support this observation from space.

• 한국수소및신에너지학회논문집
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• 제19권1호
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• pp.64-70
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• 2008

This paper briefly discusses the main sources of errors and their solutions for measuring hydrogen uptake from gas phase by the Sieverts technique. Correction of volumetric errors of apparatus, density of hydrogen storage material, estimation of temperature gradient are investigated. Systematic errors and the change of density of the host material according to the pressure have been the subject of much controversy in recent years. We considered the standard ball calibration, temperature gradient distribution, pretreatment of hydrogen storage materials to minimize errors. We could lessen the miscalculations after applying those methods to Equilibrium pressure-composition isotherm data.

• Membrane and Water Treatment
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• 제2권4호
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• pp.267-279
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• 2011

At steady state, the simultaneous transport of sulphuric acid and nickel sulphate through an anion-exchange membrane Neosepta-AFN (Astom Corporation, Tokyo, Japan) was investigated in a two-compartment counter-current dialyzer with single passes. The transport was quantified by the recovery yield of acid, rejection of salt and four phenomenological coefficients, which were correlated with the acid and salt concentrations in the feed. The phenomenological coefficients were determined by the numerical integration of the basic differential equations describing the concentration profiles of the components in the dialyzer. This integration was combined with an optimizing procedure. The experiments proved that the acid recovery yield is in the limits from 63 to 91 %, while salt rejection is in the limits from 79 to 97 % in the dependence on the volumetric liquid flow rate and composition of the feed.

• KSBB Journal
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• 제21권6호
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• pp.493-497
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• 2006

볏짚 가수분해물의 조성과 유사한 xylose/glucose 혼합배지를 이용하여 Candida mogii ATCC 18364에 의한 xylitol 생산성 및 수율에 관한 연구를 수행하였다. 통기량을 생육단계 (약 10시간)는 호기적인 2 vvm, 300 rpm에서, 생산단계는 반호기적 조건인 1 vvm, 300 rpm으로 조절한 결과 균체의 농도가 10시간 만에 약 $4.7\;g/{\ell}$까지 증가하여 농축균을 사용한 것과 같은 효과를 얻을 수 있었으며, 4일 후에 $0.58\;g/{\ell}$의 수율과 $0.25\;g/{\ell}{\cdot}h$의 생산성으로 약 $24\;g/{\ell}$의 자일리톨이 생산되어 농축균을 이용한 것보다 약간 더 우수하였다. 또한 생산단계에서 xylose를 이용한 세포의 성장을 감소시키기 위해 생산단계에서 포도당을 $6.8\;g/{\ell}{\cdot}day$로 공급한 결과 4일 후에 0.8 g/g의 수율과 $0.31\;g/{\ell}{\cdot}h$의 생산성으로 약 $29.4\;g/{\ell}$의 자일리톨을 생산하여, 포도당 공급을 하지 않았을 때보다 약 $20{\sim}30%$의 증가를 보여주었다.

• Journal of the Korean Wood Science and Technology
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• 제43권4호
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• pp.421-428
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• 2015

본 연구는 5개 종자 산지(Carleton, Simcoe, Chatham, Bancroft, Unknown)의 루브라참나무(Quercus rubra)를 대상으로 해부학적 성질을 조사하여, 이들의 종자산지 간 및 생장속도와의 관계를 규명하였다. 루브라참나무는 환공재로서 공권부는 대형도관이 1~3열로 배열하다가 공권 외부는 소형도관이 방사상으로 배열하였다. 산지 간에는 조재부 목섬유 길이, 조재부 도관의 직경에서만 차이가 있었다. 생장속도와는 목섬유 길이 및 도관요소 직경에서 만재부는 상관관계가 없고, 조재부는 부의 상관이었다. 도관요소 길이는 생장속도와 조, 만재에서 관계가 없었다. 조, 만재부에서의 구성요소 비율은 목섬유, 방사조직은 만재부에서 높았고, 도관요소는 조재부에서 높았다. 방사조직 높이는 11~15개 범위였다.

• 한국건축시공학회지
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• 제11권6호
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• pp.547-556
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• 2011

경화 콘크리트의 물성에 있어서 황산염 저항에 가장 큰 영향을 미치는 두 요소로서 포틀랜드 시멘트의 화학적 성분과 그 양을 들 수 있다. 본 연구에서는 황산염 침투에 대한 영향을 고찰하기 위하여 ASTM C1012의 규정을 바탕으로 여러 종류의 모르타르를 제작하여 실험을 수행하였다. 본 연구에서 황산염 침투에 대한 영향을 평가하기 위해 TYPE I, 두 가지의 TYPE I-II 시멘트와 TYPE V의 시멘트 등 네 가지 모르타르를 사용하여 실험을 수행하였다. 또한 각각의 모르타르 혼합물들에 사용된 무기혼합물의 경우에도 세 가지 종류를 사용하였다. F타입 플라이애시와 C타입 플라이애시, 고로슬래그를 부피비를 기준으로 대체하여 사용하였으며, 실험을 통한 콘크리트의 팽창률을 ASTM 규정의 권장 팽창 기준을 바탕으로 비교 분석하였다.

• 대한기계학회논문집B
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• 제22권4호
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• pp.499-509
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• 1998

In the absorption process of water vapor in a liquid film, the composition of the gas phase, in which a non-absorbable gas is combined with the absorbate influences the transport characteristics remarkably. In the present study, the absorption processes of water vapor into aqueous solution of lithium bromide in the presence of non-absorbable gases were investigated analytically. The continuity, momentum, energy and diffusion equations for the solution film and gas phase were formulated in integral forms and solved numerically. It was found that the mass transfer resistance in gas phase increased with the concentration of non-absorbable gas. However the primary resistance to mass transfer was in the liquid phase. As the concentration of non-absorbable gas in the absorbate increased, the liquid-vapor interfacial temperature and concentration of absorbate in solution decreased, which resulted in the reduction of absorption rate. The reduction of mass transfer rate was found to be significant for the addition of a small amount of non-absorbable gas to the pure vapor, especially at the outlet of an absorber where non-absorbable gases accumulated. At higher non-absorbable gas concentration, the decrease of absorption flux was almost linear to the volumetric concentration of non-absorbable gas.