• International Journal of Contents
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• v.15 no.4
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• pp.97-106
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• 2019

EMI (English as a Medium of Instruction) classes are now accepted policy at Korean universities, yet students often struggle with required academic English writings. The present study examined an EMI class that used direct instruction and access to online assistive English writing software. From preliminary analysis, 26 students expressed interest in how an EMI academic writing class could facilitate improved English writing skills. Study participants completed a survey on self-efficacy and learning needs and assignments for an EMI academic writing class. To establish inter-rater reliability, three trained raters assessed the written essays of students prior to and after instructional intervention. Fleiss' Kappas statistics showed moderate reliability. Students' opinions on the use of online software were also analysed. Paired t-test was run on the quality of students' pre- and post-instruction assignments, and there was significant difference in the rated scores. Self-efficacy was found to have moderate positive association with improved post-essay writing scores.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2004.10a
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• pp.222-225
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• 2004

Alloy 718 is normally used for the stationary and rotating parts of gas turbines due to its excellent combination of high temperature mechanical properties, formability and weldability. The mechanical properties of the Alloy 718 depend very much on grain size, as well as the strengthening phases, ${\gamma}'\;and\;{\gamma}'$. Direct aging is normally used to enhance tensile strengths at high temperatures. The grain structure of the superalloy components is mainly controlled during thermo-mechanical process by the dynamic, meta-dynamic recrystallization and grain growth. In this study, the influence of grain structure and heat treatment on tensile properties of direct-aged Alloy 718 was evaluated.

• Journal of Welding and Joining
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• v.19 no.2
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• pp.98-103
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• 2001

Root gap out of standard by welding deformation is frequently produced at butt weld joints of steel bridge. For example although standard root gap is below 6mm at butt weld joints of plates under 15mm thickness. maximum 35mm root opening is produced at the weld field. At this case, the part out of standard is generally built up and the rest part is welded by WPS. Direct welding without built-up welding is preferred in weld field because built-up welding process bring about the cost-up at manufacturing. To apply this direct weld to root gap out of standard, the investigation about mechanical properties and fatigue at weldment is required. Inthisstudy, therefore the verification for direct weld without built up is performed at weldment as root gap. It includes tension, bending. hardness, impact and fatigue test for each welding specimen of 6mm, 25mm, 35mm root gap.

• Macromolecular Research
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• v.10 no.4
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• pp.181-186
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• 2002

The displacement of carbon black to polypyrrole as a catalyst supporter in the fuel electrode of a direct methanol fuel cell was investigated. Polypyrrole was obtained as a black powder by the chemical polymerization of pyrrole with three different oxidants. The synthesized polypyrroles were pasted on carbon paper and transformed to the fuel electrodes with electrochemically deposited platinum. The prepared fuel electrode was assembled and mounted in a unit cell using a membrane and cathodic electrode film. In comparison with the carbon black fuel electrode, the performance of the unit cell was analyzed in relation to the state of the catalyst, the type of oxidant, and the morphology of the polypyrrole powder.

• Journal of ILASS-Korea
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• v.23 no.2
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• pp.96-101
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• 2018

The purpose of this study is to investigate the effect of water injection on combustion characteristics of gasoline direct injection (GDI) engine with turbo-charger under low-load operating condition. The test engine used in this study has four-cylinder and 10.2 of compression ratio. In order to study the effect of water injection ratio on combustion characteristics, the water was injected into the intake port from 10% to 50%, based on fuel injection quantity. From the experiment, it revealed that the water injection induced the improvement of fuel economy because of the advance of spark-timing by the reduction of in-cylinder temperature. In addition, the water injection caused the prolong of extension of the ignition delay and slight increase of burn duration.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2001.10a
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• pp.713-716
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• 2001

This paper describes Direct load control(DLC) method including unit commitment. To consider the unit commitment on DLC, 3-Dimensional dynamic programming as a new unit commitment method is developed. And, this method is applied to DLC. As result, optimization of operating schedule with DLC is possible. This method is applied to the test system, and usefulness of the method is verified.

• Journal of Industrial Technology
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• v.18
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• pp.329-334
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• 1998

The purpose of this study is to design and manufacture a vibration exciter, which can be used in the education and research for the vibration engineering. For this purpose, a direct drive type vibration exciter is developed, which consists of a motor, an inverter, eccentric rotating sleeves and two excitation plates. Developed exciter is tested on some dynamic characteristics to evaluate its excitation performance. Test results show that the developed machine can excite bodies on the horisontal vibrating plates in x,y direction by the constant displacement amplitude in the frequency range below 50Hz, which confirm that the exciter can be used as a vibration testing machine in the low frequency range.

• Journal of Hydrogen and New Energy
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• v.25 no.4
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• pp.419-424
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• 2014

Direct ethanol fuel cell has been fabricated with ceramic membrane. A porous silicon carbide (SiC) membrane having approximately 30% porosity has been applied for a direct ethanol proton exchange membrane (DE-PEM) fuel cell. A horizontal type cell having Pt ($18mg/cm^2$) catalyst layer on both side of the ceramic membrane was used for the demonstration test. The ethanol oxidation based-fuel cell stack showed very high voltage (1.289V) and measurable current level (68mA) even though at room temperature.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.11a
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• pp.149-152
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• 2001

In this paper, aging diagnosis method of CV cable was investigated. CV cable was designed for the sake of using during 30 years. Therefore it was important to evaluate the cable's remaining life because CV cable used for power transmission line since 1970's. CV cable was mainly installed at the underground owing to the environmental condition. If the cable accident occurred, it needs the much time for the accident recovery and the much damage at the industrial activity. therefore, this paper should study the direct leakage current method, a sort of the cables'aging test method.

• 한국연소학회:학술대회논문집
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• 2013.06a
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• pp.33-35
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• 2013

The present work is an experimental investigation on potential operating range using directly injected gasoline fuel in a single-cylinder compression ignition (CI) engine. The objectives of present study were to apply auto-ignited combustion to gasoline fuel and to evaluate potential operating range. In order to auto-ignite gasoline fuel in CI engine, the fuel direct-injection system and the intake air system were modified that a flow rate and temperature of intake air were regulated. The heat-release rate (HRR), net indicated mean effective pressure (IMEP), start of combustion (SOC), and combustion duration were derived from in-cylinder pressure data in a test engine, which has 373.33cc displacement volume and 17.8 compression ratio. The exhaust emission characteristics were obtained emission gas analyzer and smoke meter on the exhaust line system.