• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2008.10a
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• pp.479-482
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• 2008

사고력 신장 교육은 정보영재를 위한 교육과정 및 내용 중에서 매우 중요한 목표이다. 이 논문에서는 정보영재 교육에서 중요성이 증대되는 사고력 신장 교육에 적합한 교수-학습 프로그램을 제시하여 적용하고 분석하는 방안을 마련한다. 사고력 신장 교육을 구성하는 영역별 교육 내용에 포함되는 여러 가지의 문제들에 공통적으로 적용할 수 있는 모형으로서 AND/OR 트리에 기반을 둔 교수-학습 모형을 제시한다. 이 논문에서 제시된 AND/OR 트리형 교수-학습 모형을 정보영재의 현장 교육에 도입하기 위하여 tic-tac-toe 게임 문제를 예로 들어 적용 방안을 제시하며, 그 적용 결과를 분석하여 교육 프로그램 개발의 타당성을 검증한다. AND/OR 트리형 교수-학습 모형에서는 AND 트리와 OR 트리가 결합된 형태의 트리 구성과 그에 따른 트리 탐색을 주요 학습 내용으로 하는 고도의 사고력을 필요로 하는 학습 단계를 필요로 한다.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.08a
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• pp.95-95
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• 2010

An apparatus for generating flames and more particularly the microwave plasma burner for generating high-temperature large-volume plasma flame was presented. The plasma burner was composed of micvrowave transmission lines, a field applicator, discharge tube, coal and gas supply systems, and a reactor. The plasma burner is operated by injecting coal powders into a 2.45 GHz microwave plasma torch and by mixing the resultant gaseous hydrogen and carbon compounds with plasma-forming gas. We in this work used air, oxygen, steam, and their mixtures as a discharge gas or oxidant gas. The microwave plasma torch can instantaneously vaporize and decompose the hydrogen and carbon containing fuels. It was observed that the flame volume of the burner was more than 50 times that of the torch plasma. The preliminary experiments were carried out by measuring the temperature profiles of flames along the radial and axial directions. We also investigated the characteristics for coal combustion and gasification by analyzing the byproducts from the exit of reactor. As expected, various byproducts such as hydrogen, carbon monoxide, carbon dioxide, hydrogen sulfide, etc. were detected. It is expected that such burner cab be applied to coal gasification, hydrocarbon reforming, industrial boiler of power plants, etc.

• Journal of the Korea institute for structural maintenance and inspection
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• v.7 no.2
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• pp.219-229
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• 2003

The objective of this work is to verify the Code specified girder distribution factors for short and medium span bridges. To accomplish this objective, field tests were carried out on seventeen simply supported highway bridges. This paper presents the procedure and results of field tests that were performed to verify girder distribution factors. Finite Element analyses previously performed at the University of Michigan indicated that in most cases currently used girder distribution factors specified in AASHTO Codes are too conservative. However, these studies also showed that for short spans and short girder spacings, the girder distribution factors can be too permissive. Therefore, this paper focused on experimental evaluation of girder distribution factors for short and medium span steel girder bridges. The results were compared with the distribution factors specified by AASHTO Standard (2000) and AASHTO LRFD Code (1998). It has been found that the measured girder distribution factors are lower than AASHTO values in most cases, and sometimes the code specified values are overly conservative. The research work involved formulation of the testing procedure, selection of structure, installation of equipment, measurements, and interpretation of the results.

• Journal of the Korea institute for structural maintenance and inspection
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• v.19 no.1
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• pp.3-12
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• 2015

Bursting stress in anchorage zone of post tension girder can be estimated based on Guyon's equation. The major parameters in calculating bursting stress are prestressing force and the distance ratio between concrete edge and anchorage plate. Although Guyon's equation can be applied to calculate bursting stress for rectangular typed as well as circular typed plate, there is some limitation of accuracy due to 2 dimensional analysis. Therefore this study is proposed to suggest a bursting stress equation based on 3 dimensional finite element method.

• Clinical and Experimental Pediatrics
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• v.50 no.3
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• pp.302-305
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• 2007

As a result of the widespread use and enhanced quality of high-resolution radiological techniques, a recent report has revealed a relatively high prevalence of small adrenal tumors in patients with untreated congenital adrenal hyperplasia due to 21-hydroxylase deficiency. However, there are scarcely any pediatric cases of adrenocortical tumor following long-term treatment in patients suffering with congenital adrenal hyperplasia. We report here on a pediatric female case of adrenocortical adenoma despite adequate long-term treatment for the salt-losing type of congenital adrenal hyperplasia.

• Korean Journal of Food Science and Technology
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• v.19 no.2
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• pp.97-101
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• 1987

Physicochemical properties of heat-moisture (18, 21, 24 and 27%) treated naked barley (Youngsanbori) starch indicated that crystailinity of the starch was decreased upon treatment and water-binding capacity drastically increased as the moisture level increased. The swelling power was decreased, but the solubility increased by heat-moisture treatment. Apparent viscosity in aqueous sodium hydroxide solution was repressed as moisture-treatment level increased. Amylograph hot paste vicosities were decreased upon treatment except initial pasting temperature.

• Journal of Korean Society on Water Environment
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• v.28 no.3
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• pp.367-374
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• 2012

A flotation process has a shorter processing time and needs less space than a sedimentation process. Dissolved air flotation process (DAF) is an efficient flotation method and used in a conventional wastewater treatment process. However, DAF requires the circulation of water containing compressed air and requires expensive installation and operation cost. Plasma Air Flotation (PAF) process is able to float flocs by micro bubbles generated from underwater plasma without the circulation of bubbly water and additional saturators. Therefore, PAF can be an alternative solution overcoming economic barriers. In this study, Humic acid removal efficiency by PAF process was compared with that of sedimentation process. 44.67% and 87.3% reduction rate based on UV 254 absorbance has been measured in sedimentation and PAF respectively. In particular, PAF in the flocculation zone can dramatically remove humic acid from water. In flocculation zone, PAF can separate organic matters but sedimentation cannot.

• Journal of Surface Science and Engineering
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• v.42 no.3
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• pp.139-144
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• 2009

A microwave plasma torch at the atmospheric pressure by making use of magnetrons operated at the 2.45 GHz and used in a home microwave oven has been developed. This electrodeless torch can be used to various areas, including industrial, environmental and military applications. Although the microwave plasma torch has many applications, we in the present work focused on the microwave plasma torch operated in pure steam and several applications, which may be used in future and right now. For example, a high-temperature steam microwave plasma torch may have a potential application of the hydrocarbon fuel reforming at one atmospheric pressure. Moreover, the radicals including hydrogen, oxygen and hydroxide molecules are abundantly available in the steam torch, dramatically enhancing the reaction speed. Also, the microwave plasma torch can be used as a high-temperature, large-volume plasma burner by injecting hydrocarbon fuels in gas, liquid, and solid into the plasma flame. Finally, we briefly report treatment of soils contaminated with oils, volatile organic compounds, heavy metals, etc., which is an underway research in our group.

• Journal of the Korean Society for Railway
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• v.14 no.5
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• pp.411-415
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• 2011

DC/DC switching power converters are commonly used to generate a regulated DC output voltages with high efficiencies from different DC input sources. The voltage mode DC/DC converter utilizes MOSFET (metal-oxide semiconductor field effect transistor), inductor, and a PWM (pulse-width modulation) controller with oscillator, amplifier, and comparator, etc. to efficiently transfer energy from the input to the output at periodic intervals. The fundamental boost converter and a buck converter containing a switched-mode power supply are studied. In this paper, the electrical characteristics of DC/DC power converters are simulated by program of SPICE, and the PWM controller is implemented to check the operation. In addition, power efficiency is analyzed based on the specification of each component.

• Environmental and Resource Economics Review
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• v.10 no.2
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• pp.235-257
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• 2001

As in other Asian countries, the Korean government provides direct subsidies to endeavors that are potentially harmful to the environment. The water sector is one of the main recipients of these subsidies. The total amount of estimated direct fiscal subsidies equals 2.200 trillion won; however, the comprehensive cost of the subsidies is estimated to be much greater because environmental and social costs were not considered in the initial calculation. Most of the fiscal direct subsidies in the water sector are subsidized to urban water areas. The percentage of fiscal direct subsidies in the urban water sector to the total fiscal direct subsidies is 79.68%, while the percentage of fiscal direct subsidies in the industrial water sector is only 4.92%. Since the ratio of fiscal direct subsidies in the industrial water sector is quite small, the negative impact of removing fiscal direct subsidies for the industrial sector may be trivial. If the Korean government cuts dowm the VAT or income tax rate while reducing several types of subsidies, it will be able to achieve a double dividend effect both on the economy and the environment.