• Clean Technology
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• v.18 no.4
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• pp.426-431
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• 2012

Carbon-rich coal can be utilized as a fuel for direct carbon fuel cell (DCFC). However, left-behind ash after the electrochemical oxidation may hinder the electrochemical reactions. In this study, we produced ash-free coal (AFC) by thermal extraction and then tested it as a fuel for DCFC. DCFC was built based on solid oxide electrolyte and the electrochemical performance of AFC mixed with $K_2CO_3$ was compared with AFC only. Significantly enhanced power density was found by catalytic steam gasification of AFC. However, an increase of the power density by catalytic pyrolysis was negligible. This result indicated that a catalyst activated the steam gasification reactions, producing much more $H_2$ and thus increasing the power density, compared to AFC only. Results of a quantitative analysis showed much improved kinetics in AFC with $K_2CO_3$ in agreement with DCFC results. A secondary phase of potassium on yttria-stabilized zirconia (YSZ) surface was observed after the cell operation. This probably caused poor long-term behavior of AFC with $K_2CO_3$. A thin YSZ (30 ${\mu}m$ thick) was found to be higher in the power density than 0.9 mm of YSZ.

• Journal of the Korea institute for structural maintenance and inspection
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• v.21 no.5
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• pp.42-48
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• 2017

When concrete structures expose to fire, the structures were damaged accompanied with degradation of material properties of concrete. In order to determine the reuse of fire-damaged concrete structures, it is needed a careful determination considering conditions of fire damage, such as exposure temperature and exposure time, and also potential to restore fire damage. This study investigates on the evaluation of residual material properties of fire-damaged concrete under different post-fire curing regimes. An experimental study was performed on concrete samples to measure the dynamic elastic modulus by the impact resonance vibration method. Upon the experimental results, the evidence of restoration of material properties was confirmed on specific post-fire curing regimes, higher humidity conditions. Additionally, a correlation analysis was performed on the dynamic elastic modulus with the tensile strength for identifying the effects of post-fire curing regimes on both material properties of fire-damaged concrete.

• Journal of Technology Innovation
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• v.18 no.2
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• pp.221-252
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• 2010

This study presents a concept of technology trade network and management, and proposes a procedural method for optimally selecting the technology transferor when a technology transferee needs to buy a specific technology. We develop a technology trade network where technology supplier, technology marketer, and technology transferee are informatively linked. And a technology trade management consists of three step of estimating technology, trading technology, and commercialization technology. Technology transferees could import the best appropriate technology which they want through these technology network method and cost optimization method. And we hope that these methodologies can be used in selecting new technology. A methodology can be classified into an estimating technology process and a choice of technology supplier process. In an estimating technology process, we calculate the technology similarity quantitatively through developing method of estimating technology which is focused on its technological characteristics. After defining the related cost of technology introduction, we suggest goal programming model to find a solution which can be acceptable both maximizing the technology similarity and minimizing the cost of technology. And suggested model is verified with a supplier selection problem of next generation tanks.

• Applied Chemistry for Engineering
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• v.28 no.5
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• pp.593-596
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• 2017

Sodium titanate nanosheets were prepared by a hydrothermal synthesis method under basic conditions. Ruthenium was introduced on the surface of sodium titanate nanosheets through an UV irradiation in the aqueous $RuCl_3$ solution. The crystal phase and morphology of synthesized samples were analyzed by X-ray diffraction, transmission electron microscopy and energy dispersive spectroscopy. In addition, the content of Ru was evaluated by inductively coupled plasma. It was proposed that a monomeric form of ruthenium was incorporated on the surface of sodium titanate. Ruthenium incorporated sodium titanates were applied to alcohol oxidation using molecular oxygen as an oxidant. The sample with 7% ruthenium showed a catalytic activity with a turnover frequency value of $2.1h^{-1}$ in oxidizing benzyl alcohol to benzaldehyde without any other byproducts at $105^{\circ}C$ and 1 atmosphere.

• Journal of the Korean Society for Railway
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• v.13 no.6
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• pp.595-600
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• 2010

The Bimodal Tram being developed in Korea is a new transit system that provides both benefits of rail and bus systems in terms of accessibility and fixed time schedule. The Bimodal Tram is expected to take an important role of transit system in Korea under the national strategy of transportation system such as 'Low Carbon and Green Growth' for the next generation. This study does define the key indices considered for a decision of introducing the Bimodal Tram system and develop a finalized index, BSI(Bimodal Score for Introduction), showing the level of Bimodal Tram system introduced at a city level. The transport/transit system varies depending on cities with respect to demographic characteristics, travel patterns, financial capabilities, etc. This study will help any cities where transport agencies are trying to introduce the Bimodal Tram as a new transit system.

• Journal of the Korean Society of Hazard Mitigation
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• v.2 no.3 s.6
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• pp.119-125
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• 2002

The objective of this study is to evaluate elastic modulus of bridge-axis direction for optimum structure system in the cable-stayed bridge design. In numerical example of this study, a slight change in axis direction elastic modulus causes major modifications of the bridge characteristics when it is $1\times10^4$ tonf/m/bearing or less. Therefore, the elastic modulus was set at this lower limit of $1\times10^4$ tonf/m/bearing where the strength of the entire bridge system is still determined by girder strength and the entire system is insensitive to variations in elastic modulus. Besides, cable-stayed bridge with freely supported girders have slightly longer vibration periods in the horizontal direction for earthquake forces.

• Water for future
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• v.21 no.1
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• pp.67-76
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• 1988

Analyzed was the circulation phenomena in the open channel with sudden expansion, by applying the Galerkin's finite element method to the depth-averaged 2-dimensional continuity and momentum equations. Wave tests were done in the simplified channel in order to review the validity of this newly developed model and the computed results were within 0.5% of $L_2$-norm error, and application of this model to the simulation of simplified dam-break gave very close results compared with the analytical solution, thus, it can be concluded that this model is valid and efficient. The main flow in the expanded channel was defined as a new initial condition with given velocity and the flow in the expanded portion was at rest in simulating the circulation, and besides the Neumann's condition the slip boundary condition for lateral wall was found to be proper condition than the no-slip condition. It can be concluded, from the numerical tests in the sudden expension, that the circulating phenomena depend mainly on the convective inertia and the effect of turbulence due to bottom shear and lateral shear is insignificant.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.12 no.1
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• pp.7-12
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• 2006

The EU regulation of overall migration which is the cornerstone of the limitation to ensure that plastic materials and articles intended to contact with foodstuffs are fit for the intended application, was reviewed. In Council Directives, it was established in detail what simulants, contact times and temperatures are to be used in migration tests performed under standardized conditions. In some cases, conventional conditions for substitution test was provided, because of technical reasons. Moreover, a reduction factor ranging from 2$\sim$5 may be applied depending on the foods, because olive oil which is simulant for fatty foods, is severe solvent compared with most fatty food.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2004.05a
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• pp.269-272
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• 2004

비즈니스 프로세스 관리(BPM)는 프로세스의 모델링, 분석, 실행에 이르는 비즈니스 프로세스 전 라이프 사이클을 지원하고자 하는 개념으로, 급변하는 경영 환경의 변화에서 기업의 경쟁력을 재고하기 위하여 필요로 되는 새로운 기업 컴퓨팅 패러다임이다. 비즈니스 프로세스 관리의 개념을 도입함으로써 기업들은 조직의 프로세스를 능동적이고 빠르게 (재)설계하고 수행할 수 있으며, 기업간 M&A 및 전략적 제휴를 효율적으로 수행할 수 있다. 기업간 협업이 이루어지기 위해서는 그들 간의 프로세스의 교류 및 통합이 필수적이다. 통합의 한 수단으로 여러 프로세스에 관련된 Data들을 Rule의 형태로 표현하여 관리할 수 있다. 본 연구에서는 워크플로, BPMS 등의 환경에서 비즈니스 Rule을 포함하는 비즈니스 프로세스 수행시에 관리해야 할 제약조건을 통합 관리할 수 있는 방법론을 제시한다. 비즈니스 프로세스를 수행하면서 체크해야 할 제약조건들을 규명한후 이들을 표현할 수 있는 프로세스 기반의 트리거 모델을 제시한다. 또한 본 방법론의 실현 가능성을 보여주기 위해 예제와 함께 프로토타입 시스템을 구현하였고 Performance 측면에서는 제한적이기는 하지만 DB에 기반한 제약조건 관리방법과의 비교를 통해서 본 연구에서 제안하고 있는 방법의 우수성을 보여준다. 본 연구에서 제안하는 방법론은 Workflow 및 BPMS와 같은 프로세스 관리 시스템에서 통합의 수단으로 사용되고 있는 EAI 등을 보완해 줄수 있는 툴로써 활용가능하리라 기대된다.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.437-437
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• 2013

3족 질화물은 우수한 광학 특성과 특히 3족 물질의 조성비 조절로 넓은 대역의 밴드갭 엔지니어링으로 발광다이오드의 물질로 각광 받고 있다. 이와 더불어 발광다이오드의 광추출효율을 향상시키기 위해 다양한 연구들이 활발히 이루어지고 있다. 그 연구 중 하나로 나노, 마이크로 사이즈의 막대와 같은 일차원적 구조와 최근 ITO를 활용한 투명 전극을 대체하여 전도도가 100배 정도 높은 금속을 이용한 옆면 접촉 전극을 도입한 것이 최근 발표되었다. 그러나 옆면 접촉 전극을 형성하기 위해서는 기존의 약 100 nm 정도의 두께의 p-형질화갈륨층은 공정 마진 등에 어려움이 있다. 따라서 기존에 비해 두꺼운 p-형 질화갈륨층이 필요하다. 보통 상용화된 유기 금속화학 증착법을 이용한 p-형 질화갈륨층은 도핑 물질인 Mg의 낮은 활성화와 성장 분위기 중 수소로 인해 양질의 것을 얻기 어렵고 이를 위해 성장 후 추가적인 활성화가 필요하다. 따라서 두꺼워진 p-형 질화갈륨층에 대해서도 기존의 성장 조건과 활성화 조건의 적합 여부와 이에 대한 연구가 필요하다. 따라서 본 연구에서는 양질의 p-형 질화갈륨을 얻기 위하여 성장 조건 및 성장 후 급속 열처리 온도, 시간에 대한 최적화와 약 630 nm 두께의 p-형 갈륨질화층을 가지는 발광다이오드에 대해 급속 열처리 조건에 대한 특성 연구를 실시한다.