• Journal of Hydrogen and New Energy
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• v.22 no.6
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• pp.859-867
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• 2011

The cold start problem is one of major obstacles to overcome for the commercialization of fuel cell vehicles. However, the cold start characteristics of fuel cell systems are very complicated since various phenomena, i.e. ice-blocking, electro-chemical reactions, heat transfer, and defrosting of BOP components, are involved in them. This paper presents a framework to approach the problem at a full stack scale using Axiomatic Design (AD). It was characterized in terms of Functional Requirements (FRs) and Design Parameters (DPs) while their relations were established in a design matrix. Considering the design matrix, the endplates should have low thermal conductivity and capacity without increase in weight or decrease in structural stiffness. Consequently, composite sandwich endplates were proposed and examined both through finite element analyses and experiments simulating cold start conditions. From the examinations, it was found that the composite sandwich endplates significantly contributed to improving the cold start characteristics of PEMFC.

• Journal of Hydrogen and New Energy
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• v.20 no.6
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• pp.512-518
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• 2009

Mg 및 Mg합금은 수소 저장량이 7.6wt.%로 비교적 높고 자원도 풍부하여 값이 싼 장점을 가지고 있으나 산화반응성이 높고 활성화 에너지가 크기 때문에 반응온도가 높고 반응시간이 긴 단점을 가지고 있다. 이러한 단점을 극복하기 위해 일반적으로 Mg 및 Mg합금의 표면 개질화, 금속간 화합물 형성, 전이금속 첨가에 대한 연구가 활발히 진행되고 있다. 본 연구에서는 전이금속인 Nb를 촉매제로 사용하여 수소화 특성을 개선하고자 기계적 합금화법(MA;Mechanical Alloying)을 실시하여 복합재료를 합성한 후 수소화 반응을 평가하였다. XRD, SEM, TEM, PSA, TG/DSC 분석을 수행하였으며 Sievert's 형 PCT를 이용하여 온도 및 압력 변화에 따른 특성평가를 하였다. 전이금속인 Nb의 첨가로 수소화 반응개시온도가 낮아지고 수소 저장량이 향상되는 거동을 보였다. 특히, 5mass%Nb가 10mass%Nb 보다 수소 저장량 및 반응속도가 좋은 결과를 보였다.

• Korean Journal of Materials Research
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• v.15 no.12
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• pp.814-817
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• 2005

In order to enhance energy efficiency in high electric conversion devices such as Power transformers, which need to have high power properties, an alloy design approach in $Pb(Zr,Ti)O_3(PZT)$ base ceramic system was attempted $0.03Pb(Sb_{0.5}Nb_{0.5})O_3-0.03Pb(Mn_{1/3}Nb_{2/3})O_3-(0.94-x)PbTiO_3-xPbZrO_3$[PSN-PMN- PZT] ceramics were synthesized by conventional bulk ceramic processing technique. To improve power properties, the various Zr/Ti ratio was varied ]lear their morphotropic phase boundary (MPB) composition of PSN-PMN-PZT system and their effects on subsequent piezoelectric and dielectric properties for the transformer application at high power were systematically investigated using an impedance analyzer. Microstructure and phase information were characterized using X-ray diffractometer (XRD), a scanning electron microscope (SEM) and others. When the Zr/Ti ratio was 0.415/0.465, the value of $Q_m\;and\;k_p$ were shown to reach to the maximum, indicating that this alloy design can be a feasible composition :or high power transformer.

• Korean Journal of Materials Research
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• v.34 no.5
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• pp.254-260
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• 2024

This study is to manufacture a titanium dioxide (TiO₂) photocatalyst by recycling sludge generated using titanium tetrachloride (TiCl₄) as a coagulant. Compared to general sewage, a TiCl₄ coagulant was applied to dyeing wastewater containing a large amount of non-degradable organic compounds to evaluate its performance. Then the generated sludge was dried and fired to prepare a photocatalyst (TFS). Scanning electron microscope-energy dispersive X-ray spectroscopy (SEM-EDX), X-ray diffraction (XRD), and nitrogen oxide reduction experiments were conducted to analyze the surface properties and evaluate the photoactive ability of the prepared TFS. After using titanium tetrachloride (TiCl₄) as a coagulant in the dyeing wastewater, the water quality characteristics were measured at 84 mg/L of chemical oxygen demand (COD), 10 mg/L of T-N, and 0.9 mg/L of T-P to satisfy the discharge water quality standards. The surface properties of the TFS were investigated and the anatase crystal structure was observed. It was confirmed that the ratio of Ti and O, the main components of TiO₂, accounted for more than 90 %. As a result of the nitric oxide (NO) reduction experiment, 1.56 uMol of NO was reduced to confirm a removal rate of 20.60 %. This is judged to be a photocatalytic performance similar to that of the existing P-25. Therefore, by applying TiCl₄ to the dyeing wastewater, it is possible to solve the problems of the existing coagulant and to reduce the amount of carbon dioxide generated, using an eco-friendly sludge treatment method. In addition, it is believed that environmental and economic advantages can be obtained by manufacturing TiO₂ at an eco-friendly and lower cost than before.

• Proceedings of the Ginseng society Conference
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• 1990.06a
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• pp.168-174
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• 1990

This study was focused on the characterization of mitochondrial DNA (mtDNA) for molecular genetically approach of energy Production related mechanism in Panax Ein.fend. The simple and efficient method of mtDNA isolation from ginseng has been developed by modification of recently advanced methods. This procedure can successfully apply to mtDNA isolation of several plants. MtDNA of etiolated shoot and one-year root were digested with restriction endonucleases, but that of 6-year root not Any difference was not observed in the restriction endonuclease digestion patterns among the ginseng variants. Molecular size of ginseng mtDNA was estimated at least 159 kb by the restriction endonuclease fragment analysis. The 4.5 kb extra band at the lane of EcoRll treatment could be observed in restriction patterns digested with the methylation sensitive endonucleases, BstN 1 and EcoRll. For construction of mitochondrial genomic library of ginseng, mtDNA was partially digested with EcoRl, and packaged with EMBL4 phage vector Genomic library was screened and purified for further research including restricttion mapping of ginseng mtDNA, and cloning of the genes. The gene of ATP synthase A subunit was cloned koto the purified EMBL4 library clone No. 16. Now, clone No. 16 is subcloned for structure gene sequence analysis.

• Proceeding of Spring/Autumn Annual Conference of KHA
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• 2009.11a
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• pp.217-222
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• 2009

This study is lately stand on the basis of the importance for global warming and environment and accept changes of the paradigm of the 21st century. also it is to start architecturial access that suggest to solutions about environment, energy and health problems in high-rise residential architecture that lately the importance for global warming and environment. Spacially since 1990, high-rise residential architecture has developed into increase rapidly, and nowdays, this has become one of the new residence type. but this have diverse problems. For this reason, this building faced neccessary to improve living space and obtain to eco-friendiness and sustainability. Therefore, this study is focused to environment-friendly architectural certification in Korea and other countries, aims to suggest planning and technical elements from this system. Through 11 cases of high-rise residential architecture certified sustainable certification system, this study drew out tendency and charateristics of main strategy elements. These analysis will express informations of current level and also suggest to direction for improvement in quality of high-rise residence.

• Journal of Ginseng Research
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• v.14 no.2
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• pp.310-316
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• 1990

This study was focused on the characterization of mitochondrial DNA (mtDNA) for molecular 9enetical approach of energy Production related mechanism in Panax ginseng. The simple and efficient method of mtDNA isolation from ginseng has been developed by modification of recently advanced methods. This procedure can successfully apply to mtDNA isolation of several plants. mtDNA of etiolated shoot and one-year root were digested with restriction endonucleases, but that of 6-year root not. Any difference was not observed in the restriction endonuclease digestion patterns among the ginseng variants. Molecular size of ginseng mtDNA was estimated at least 159 kb by the restriction endonuclease fragment analysis. The 4.5 kb extra band at the lane of EcoRII treatment could be observed in restriction patterns digested with the methylation sensitive endonucleases, BstN I and EcoRII. For construction of mitochondrial genomic library of ginseng, mtDNA was partially digested with EcoRl, and packaged with EMBL4 phage vector. Genomic library was screened and purified for further research including restriction mapping of ginseng mtDNA, and cloning of the genes. The gene of ATP synthase A subunit was cloned from the purified EMBL4 library clone No. 16. Now, clone No. 16 is subcloned for structure gene sequence analysis.

• Journal of Korean Institute of Industrial Engineers
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• v.36 no.4
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• pp.230-242
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• 2010

In this paper, an environmental monitoring and diagnosis system based on ubiquitous computing technology, shortly u-Eco Monitoring System, is proposed. u-Eco Monitoring System is designed to: 1) Collect information from the manufacturing processes via ubiquitous computing technology, 2) Analyze the current status, 3) Identify the cause of problem if detected by rule-based and case-based reasoning, and 4) Provide the results to the operator for proper decision making. Based on functional modeling, a generic architecture is derived, followed by application to a manufacturing system in iron and steel making industry. Finally, to show the validity of the proposed method, a prototype is developed and tested. The developed methods can be used as a conceptual framework for designing environmental monitoring and diagnosis system for industrial practices by which monitoring accuracy and response time for abnormal status can be significantly enhanced, and relieving operator pressure from manual monitoring and error-prone decision making.

• Korean Institute of Interior Design Journal
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• v.22 no.2
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• pp.157-166
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• 2013

The underground space of urban entertainment center can do various roles for urban development. Especially, the design of underground space using natural elements is necessary to sustainable development of facilities. The purpose of this study is to propose the elements, characteristics and application around interior environmental design using natural elements in underground space of urban entertainment center. The research methods of this study are research references, survey and field-study. This study can be concluded as follows; First, the factors of interior environmental design using natural elements in underground space of urban entertainment center are 'landmarks expression of natural elements', 'introduction and planning of daylighting', 'planning of materials using natural images', 'planning of ecological footpath' and 'planning of energy recycling'. Second, pedestrian space and openspace considering regional context are necessary. Third, introduction of daylight and design of artificial lighting in underground space are needed to making eco-friendly environment. Fourth, landmark design using various natural elements in underground space is needed to provide eco-friendly amenity. Fifth, the interior environmental design using natural elements is needed to community space in underground space. Sixth, eco-friendly pedestrian space in underground space is necessary. Seventh, interior environmental design using natural elements is needed to the entrance of underground space of urban entertainment center.

• Korean Institute of Interior Design Journal
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• v.22 no.4
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• pp.158-166
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• 2013

The purpose of this study is to suggest a direction for eco-friendly healing space design for healthcare facilities in the future. Theoretical review and case study on the concept of sustainable design, spatial expression and behavioral affordance were used as research method. Through these reviews, the 3 elements of the total healing environment -physical, psychological and social- have correspondence with elements of spatial expression; Refuge, Flow, Prospect and Void. And these are related to the eight kinds of Behavioral affordance which are subdivided into WORK&STUDY, REST, CIRCULATION, VISUAL SEQUENCE, SOCIAL EXCHANGE, REFRESHMENT, COMMUNITY and MEDITATION. And the concept of sustainable design consists of 6 principles ; Natural system, People, Place, The cycle of life, Energy & natural resources and Process. Through correlation analysis of behavioral affordance and 6 principles, the result of this study presents that the physical elements of the total healing space was mainly associated with the principles of people, place and the cycle of life. Psychological element was related to principle of natural system, human, place and process. And social element was associated with the principles of human, place and process. According to this analysis, the case study of four low-rise eco-friendly medical facilities was undertaken. Sustainability was evaluated in total healing environmental through this case study.