• Journal of Electrochemical Science and Technology
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• 제12권3호
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• pp.302-307
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• 2021

Polymer electrolyte membrane (PEM) electrolyzer or alkaline electrolyzer is required to produce green hydrogen using renewable energy such as wind and/or solar power. PEM and alkaline electrolyzer differ in many ways, instantly basic materials, system configuration, and operation characteristics are different. Building an optimal water hydrolysis system by closely grasping the characteristics of each type of electrolyzer is of great help in building a safe hydrogen ecosystem as well as the efficiency of green hydrogen production. In this study, the basic operation characteristics of a kW class alkaline water electrolyzer we developed, and water electrolysis efficiency are described. Finally, a brief overview of the characteristics of PEM and alkaline electrolyzer for large-capacity green hydrogen production system will be outlined.

• 한국주거학회논문집
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• 제22권5호
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• pp.111-119
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• 2011

In recent years, the insistence that the central government should hand over the right of establishing and managing housing policies to local governments is growing. And, it is needed that local governments should pursue their own original housing policies. The purpose of this study is to explore the characteristics of the prefectural plans of the national basic act for housing in Japan to envision the future directions of regional housing policies. This study analyzed the structure, main policy contents, and the outcome indexes of all 47 prefectures' plans in Japan. The major results of this study are as follows. 1) The central government and local governments shared their roles appropriately. In addition, the local governments proactively demonstrated the unique quality of their regions when establishing their housing policies. 2) In promoting housing policies, they focused on the housing stock and the market including both public and private sectors. 3) The policy-oriented goals and performance management practices were clearly presented.

• ETRI Journal
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• 제27권6호
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• pp.685-690
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• 2005

DC and RF characteristics of $0.15{\mu}m$ GaAs power metamorphic high electron mobility transistors (MHEMT) have been investigated. The $0.15{\mu}m{\times}100{\mu}m$ MHEMT device shows a drain saturation current of 480 mA/mm, an extrinsic transconductance of 830 mS/mm, and a threshold voltage of -0.65 V. Uniformities of the threshold voltage and the maximum extrinsic transconductance across a 4-inch wafer were 8.3% and 5.1%, respectively. The obtained cut-off frequency and maximum frequency of oscillation are 141 GHz and 243 GHz, respectively. The $8{\times}50{\mu}m$ MHEMT device shows 33.2% power-added efficiency, an 18.1 dB power gain, and a 28.2 mW output power. A very low minimum noise figure of 0.79 dB and an associated gain of 10.56 dB at 26 GHz are obtained for the power MHEMT with an indium content of 53% in the InGaAs channel. This excellent noise characteristic is attributed to the drastic reduction of gate resistance by the T-shaped gate with a wide head and improved device performance. This power MHEMT technology can be used toward 77 GHz band applications.

• 응용통계연구
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• 제17권1호
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• pp.13-26
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• 2004

경제성장이론에 의하면 특정 산업에 종사하는 사업체들의 입지 행태는 업종별로 서로 공간적 관련성을 갖는다. 본 연구에서는 음이항분포의 산포모수의 특성을 이용하여 산업 활동의 공간집적도를 계량화하기 위한 산업집중지수를 정의하고 이를 이용하여 특정업종에 종사하는 사업체들의 입지행태에 있어서 공간적 변화경향을 통계적으로 규명하고자 하였다. 1995년도와 2000년도의 사업체 기초통계조사 자료를 이용하여 충북지역의 지식기반산업 7개 업종과 주력기간산업 9개 업종에 대해 산업집중지수를 추정하여 이를 기반으로 업종별 사업체들의 공간적 입지행태 변화경향을 분석하였고 지역산업 활성화에 필요한 업종의 선택 및 집중화문제해결에 산업집중지수가 활용될 수 있음을 보였다.

• 대한조선학회 특별논문집
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• 대한조선학회 2015년도 특별논문집
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• pp.56-62
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• 2015

In ship structure, many parts are in contact with inner or outer fluid as stern, ballast and oil tanks. Fatigue damages are sometimes observed in these tanks which seem to be caused by resonance with exciting force of engine and propeller. Vibration characteristics of these tanks in contact with fluid are significantly affected by fluid coupling effect. Therefore it is important to exactly predict vibration characteristics of tank structure. In order to estimate the vibration characteristics, the fluid-structure interaction(FSI) problem should be solved precisely. But it is difficult to estimate exactly the magnitude of the fluid coupling effect because it has some problems such as a fluid-structure interaction, influence by the free surface, vibration modes of structural panels and depth of water. In this paper, with fluid coupling effect, the effect of structural constraint between panels on the vibration characteristics are investigated numerically and discussed.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2009년도 춘계학술대회 논문집 특별세미나,특별/일반세션
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• pp.183-188
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• 2009

The High speed electrical multiple train having a distributed electrical motor system has just been developing to aim the experimental maximum speed at 400km/h since August, 2007. This project comes in stage of basic design and so, it needs to take some review and analysis the characteristics of suspensions on the view of basic design. The vehicle model for dynamic analysis is made from the concept design model that used for the preliminary design review with Vampire program and it is modeled with three linear secondary dampers and two shear springs separated from the bush elements in previous model. The optimization technique is applied to search the proper range of linear characteristics for the suspension elements to satisfy the stability performance at speed 130m/s (about 460km/h). The results shows there are some optimum points according to the variation of primary and secondary suspension characteristics and it would be useful to make a decision to select the proper suspension elements in the precision design that will be done by the manufacturing company.

• 대한건축학회논문집:구조계
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• 제34권1호
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• pp.33-39
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• 2018

This study performed experimental validation of the hysteretic steel slit damper's basic and dependent characteristics, which should be considered for the design. The basic characteristic of the steel slit damper is used for determining design properties of non-linear analysis, such as yielding strength, yielding displacement, elastic stiffness and post-yielding stiffness. In order to evaluate dependent characteristics of the hysteretic steel slit damper, repeated deformation capacity with respect to the displacement, velocity and aspect ratio of the damper was evaluated. In this study, steel slit damper, which is widely used in Korea, was considered. The slit dampers with 55kN and 240kN of yielding strength were produced and tested. It was concluded that the slit damper's hysteresis behavior was affected by the dependent characteristics: displacement, velocity and aspect ratio. In other words, the steel slit damper's behavior was stable within limit displacement, and aspect ratio of the strut affected repeated deformation capacity of the damper subjected to large deformation. In addition, it was observed that the repeated deformation capacity abruptly decreased at the high speed range (${\geq}60mm/sec$). Furthermore, the experimental results were evaluated with the criterion of the damping device specified in ASCE7-10.

• Asian Journal of Innovation and Policy
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• 제6권2호
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• pp.111-137
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• 2017

This study analyzes a language network of Science and Technology Basic Plan, which is the basis for science and technology policy in Korea, for the next Science and Technology Basic Plan. Language network analysis was adopted for a quantitative approach measuring the trend of policies. Several techniques such as keyword analysis, language network map analysis, quantitative characteristics analysis and keyword-related major-word analysis have been performed. Results show that there are common policies emphasized by all Science and Technology Basic Plans in the past, and there are also specific policies emphasized in each period of the Science and Technology Basic Plan. These specific policies come from a 'change of times' when the Science and Technology Basic Plans were established, as well as the philosophy of the national government.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2003년도 International Meeting on Information Display
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• pp.683-685
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• 2003

We report on a surface planarization process that produces more planar surface than previous sequential lateral solidification crystallized poly silicon films. By applying the single shot laser irradiation with optimum energy density ($(817mJ/cm^{2})$ on the ridge area after SLS crystallization, the ridge height can be decreased.

• 한국지진공학회:학술대회논문집
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• 한국지진공학회 2000년도 춘계 학술발표회 논문집 Proceedings of EESK Conference-Spring
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• pp.375-382
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• 2000

This paper briefly summarizes the basic concepts and main characteristics of seismic design of New Zealand Standards(NZS) with regard to reinforced concrete(RC) structures. NZS used the concept of the capacity design and the limit state design to satisfy the requirements of serviceability and safety. Plastic mechanisms and details with respect to the limit state of safety are briefly presented in this paper. The understanding of this advanced seismic design concept will enable us to implement the basic theory of capacity design and contribute to the development of Korean seismic code in new generation,