• 한국신재생에너지학회:학술대회논문집
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• 2011.05a
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• pp.136.2-136.2
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• 2011

In this work, we analyzed correlations between life-cycle greenhouse gas (GHG) emissions and life-cycle cost of energy resources. Energy resources studied in this paper include coal, natural gas, nuclear power, hydropower, geothermal energy, wind power, solar thermal energy, and solar photovoltaic energy, and all of them are used to generate electricity. We calculated the mean values, ranges of maximum minus minimum values, and ranges of 90% confidence interval of life-cycle GHG emissions and life-cycle cost of each energy resource. Based on the values, we plotted them in two dimensional graphs to analyze a relationship and characteristics between GHG emissions and cost. Besides, to analyze the technical maturity, the GHG emissions and the range of minimum and maximum values were compared to each other. For the electric generation, energy resources are largely inverse proportional to the GHG emission and the corresponding cost.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.61 no.4
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• pp.567-573
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• 2012

Outer rotor type in-wheel Blushless DC Motor(BLDCM) for three-wheeled electric vehicle is researched. In-wheel system is to drive the electric vehicle without mechanical transmission, shaft, differential gears or other mechanical system. The motor is designed considering the performance requirements and drive modes of the vehicle. The determined dimensions as well as the slot and rotor pole are simulated by magnetic and thermal finite element analysis and ansys workbench to analyze the performance and heating of the motor. In order to verify the performance characteristics of the proposed motor, the experiment tests are executed and satisfy well the requirements.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.56 no.7
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• pp.1282-1287
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• 2007

We investigated the damage of the CMOS IC which manufactured three different technologies by high power microwave. The tests separated the two methods in accordance with the types of the CMOS IC located inner waveguide. The only CMOS IC which was located inner waveguide was occurred breakdown below the max electric field (23.94kV/m) without destruction but the CMOS IC which was connected IC to line organically was located inner waveguide and it was occurred breakdown and destruction below the max electric field. Also destructed CMOS IC was removed their surface and a chip condition was analyzed by SEM. The SEM analysis of the damaged devices showed onchuipwire and bondwire destruction like melting due to thermal effect. The tested results are applied to the fundamental data which interprets the combination mechanism of the semiconductors from artificial electromagnetic wave environment and are applied to the data which understand electromagnetic wave effects of electronic equipments.

• Journal of Powder Materials
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• v.8 no.2
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• pp.104-109
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• 2001

The semiconducting ${\beta}-FeSi_2$ compound has been recognized as a thermoelectric material with excel-lent oxidation resistance and stable characteristics at elevated temperature. In the present work, we applied mechanical alloying(MA) technique to produce ${\beta}-FeSi_2$ compound using a mixture of elemental iron and silicon powders. The mechanical alloying was carried out using a Fritsch P-5 planetary mill under Ar gas atmosphere. The MA powders were characterized by the X-ray diffraction with Cu-K $\alpha$ radiation, thermal analysis and scanning electron microscopy. The single ${\beta}-FeSi_2$ phase has been obtained by mechanical alloying of $Fe_{33}Si_{67}$ mixture powders for 120 hrs or for 70 hrs coupled with the subsequent heat treatment up to $700^{\circ}C$. The grain size of ${\beta}-FeSi_2$ powders analyzed by Hall plot method was 44nm.

• 한국연소학회:학술대회논문집
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• 1999.10a
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• pp.129-138
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• 1999

In this paper, our main issue is that establishing the control procedure of continuous gas flow rate according to combustion fan RPM. For this, first, we decide the optimum operating condition of gas swirl burner through analysis of combustion characteristics - thermal efficiency, combustion efficiency and exhaust gases such as CO, $CO_{2}$, $O_{2}$, $NO_{x}$ and THC. Second, fuel gas flow rate of gas valve is decided with considering excess air ratio and combustion fan RPM is decided by the target of combustion air flow rate. Finally, experimental operating equation is acquired by regression for gas valve and combustion fan. This equation is the control equation of continuous gas flow rate and always gas flow rate is decided by combustion fan operating RPM.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1997.04a
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• pp.314-317
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• 1997

The electrical and physical characteristics of aluminum oxide and Pt thin films on it, deposited by reactive sputtering and DC magnetron sputtering respectively, were analyzed with increasing annealing temperature(400~80$0^{\circ}C$) by four point probe, SEM and XRD. Under $600^{\circ}C$ of annealing temperature, aluminum oxide had the properties of improving Pt adhesion to SiO$_2$and insulation without chemical reaction to Pt thin films and the resistivity of Pt thin films was improved. But these properties of aluminum oxide and Pt thin films on it were degraded over $700^{\circ}C$ of annealing temperature because aluminum oxide was changed into metal aluminum and then reacted to Pt thin films deposited on it. In the analysis of the thermal charateristics of Pt micro-heater fabricated on Si07/si substrate, the temperature of Pt micro-heater is up to 41$0^{\circ}C$ with the power dissipation 1.8 watts.

• Proceedings of the KSR Conference
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• 2004.06a
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• pp.352-357
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• 2004

In this study. the effects of combined environmental factors on mechanical and thermal analysis properties of graphite/epoxy composites were evaluated through a 2.5KW accelerated environmental aging tester. Environmental factors such as temperature. moisture, and ultraviolet were considered. A xenon-arc lamp was utilized for ultraviolet light. and exposure times of up to 3000 hours were applied. Several types of specimens - tensile, bending, and shear specimens those are warp direction and fill direction were used to investigate the effects of environmental factors on mechanical properties of the composites. The glass fabric $\sharp$650/AP300 was used for the fabrication of specimens. Mechanical degradations for tensile, bending and shear properties were evaluated through a UTM. Also. storage shear modulus. loss shear modulus, and tan $\delta$ were measured as a function of exposure times through a dynamic mechanical analyzer. Finally exposed surfaces of the composites were examined using II scanning electron microscope.

• Proceedings of the KSR Conference
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• 2003.10b
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• pp.442-447
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• 2003

The actual behavior of the railroad track structure is suspected to be a complex interaction between the vertical, lateral, longitudinal, and torsional behaviors. A FE program are developed in the present study to be used for extensive nonlinear analysis of the track structures subjected to thermal load. Using the rigorous study on the deformed shape of the rail and tie, and stress resultants, characteristics of the three dimensional behavior are investigated. It is found that the flexural rigidity of the tie and the rotational stiffness of pad-fastener can be affect the behavior of the track structure and the postbuckling behavior in each rail, except lateral behavior, is not same.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.10 no.1
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• pp.95-107
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• 1998

Natural convection and radiation heat transfer in a square enclosure containing absorbing, emitting, and isotopically scattering(participating) media is studied numerically using the finite volume method. Various numerical methods are employed to analyze the radiative heat transfer. However, it is very difficult to choose the proper method. In present study, a finite volume method(FVM) and a discrete ordinates method(DOM) are compared in rectangular enclosure. The SIMPLER algorithm is used to solve the momentum and energy equations. Thermal and flow characteristics are investigated according to the variation of radiation parameters such as optical thickness and scattering albedo. The result shows that the accuracy and the computing time of FVM are better than those of DOM in regular geometry.

• Macromolecular Research
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• v.13 no.2
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• pp.141-146
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• 2005

Calix[4]crown-6-2,4-bis(4-aminobutyl ether), which has a crown-6 moiety at the 1,3-position and amino function at the 2,4-position, was prepared as an intermediate for the subsequent synthesis of calix[4]crown-6-containing polyamide and polyimide using adipoyl chloride and 1,2,4,5-benzenetetracarboxylic dianhydride. The chemical structures were characterized by IR, $^{1}H NMR$ spectroscopy and elemental analysis, and some of their physical properties, including their thermal behavior, were examined. The ion binding characteristics of the monomer and polymers for alkali metal and alkali earth metal ions were measured by liquid-liquid extraction from the aqueous phase into the organic phase. It has been observed that polyamide has a high binding ability towards various metal cations as compared to polyimide, which showed cesium ion selectivity.