• Proceedings of the KIEE Conference
• /
• 2006.11a
• /
• pp.345-347
• /
• 2006

신설 선로와 기존 선로와의 계통 연계시 상 배치에 따라 연계 후 발생하는 급격한 영상전류의 증가로 인하여 지락계전기의 동작 같은 계통에 악 영향을 미치는 현상이 일어난다. 이 논문은 송전선로의 연가철탑을 이용한 역상배치 시행여부에 따른 계통 해석과 상시 불평형률을 문경 변전소 신설에 따라 10월 가압 목표로 시공 중인 송전선로의 $1{\pi}$분기와 관련하여 ${\pi}$분기시의 이상적인 송전선로 상 배열을 분석한다.

• Proceedings of the KIEE Conference
• /
• 1999.07b
• /
• pp.969-971
• /
• 1999

Wavelet analysis is applying to many fields such as the time-frequency localization of a time series and a time varying data. In this paper, a statistical testing based Wavelet power spectrum analysis for the stationary Nino3 Sea Surface Temperature(SST) data was executed. Specially, the 95% confidence level for SST was effective in searching the periods of El-Nino using various wavelet basis functions.

• Proceedings of the KIEE Conference
• /
• 2006.04a
• /
• pp.39-41
• /
• 2006

It is important to estimate the hand skin temperature because it reveals not only physiological properties of a certain diseases but also it can estimate even human mental-stress conditions. In this study, we try to estimate the temporal skin temperature distribution of human hand by applying stress-cold test to possibly apply to estimate a subject's blood circulation condition in his or her hand in terms of normal or abnormal state.

• Proceedings of the KIEE Conference
• /
• 2000.07c
• /
• pp.1900-1902
• /
• 2000

In this paper, the temperature distribution and thermal stress analysis of mold transformer for power distribution system is investigated by FEM. Filler type epoxy is applied for good cooling effect in mold transformer.

• Proceedings of the KIEE Conference
• /
• 2006.10a
• /
• pp.57-58
• /
• 2006

As the power density and switching frequency increase, thermal analysis of power electronics system becomes imperative. The analysis provides valuable information on the semiconductor rating, long-term reliability. In this paper, thermal distribution of the Non Punchthrough(NPT) Insulated Gate Bipolar Transistor has been studied. For analysis of thermal distribution, we obtained results by using finite element simulator, Ansys and thermal distributions form experiments.

• Proceedings of the Korean Society For Composite Materials Conference
• /
• 2000.11a
• /
• pp.46-49
• /
• 2000

A decoupled thermo-~lezoelectric-mechanical model of composite laminates with surface bonded piezoelectric actuators, subjected to externally applied load, temperature change load, electric field load is developed. The governing differential equations are obtained by applying the principle of free energy and variational techniques. A higher order zigzag theory displacement field is employed to accurately capture the transverse shear and normal effects in laminated composite plates of arbitrary thickness.

• Fire Science and Engineering
• /
• v.30 no.6
• /
• pp.9-13
• /
• 2016

Anti-oxidation and flame resistant polyurethane nanofibers were prepared by electrospinning and aluminum hydroxide addition. Electrospinning was carried out under the following procedure conditions; applied voltage, 20 kV; polymer solution feeding rate, 1.2 ml/h; collector rolling speed, 120 rpm; and tip to collector distance, 15 cm. Aluminum hydroxide was added to the prepared polymer solution for electrospinning to enhance the oxidation and flame resistant properties. The thermal properties were investigated by thermogravimetric analysis to determine the polymer decomposition temperature, integral procedure decomposition temperature, final decomposition temperature, and remaining amount after thermal decomposition. The activated energy for polymer degradation was also investigated using the Horowitz-Metzger equation. The activation energy increased to more than 50%. The thermal properties of the polyurethane nanofibers were improved by a hydration reaction during the thermal decomposition of aluminum hydroxide around $300{\sim}500^{\circ}C$.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.30 no.5
• /
• pp.9-14
• /
• 2002

A higher order zig-zag plate theory is developed to accurately predict fully coupled mechanical, thermal, and electric behaviors. Both the in-plane displacement and temperature fields through the thickness are constructed by superimposing linear zig-zag field to the smooth globally cubic varying field. Smooth parabolic distribution through the thickness is assumed in the transverse deflection in order to consider transverse normal deformation. Linear zig-zag form is adopted in the electric field. The layer-dependent degrees of freedom of displacement and temperature fields are expressed in tern-is of reference primary degrees of freedom by applying interface continuity conditions as well as bounding surface conditions of transverse shear stresses and transverse heat flux. The numerical examples of coupled and uncoupled analysis demonstrate the accuracy and efficiency of the present theory. The present theory is suitable for the predictions of fully coupled behaviors of thick smart composite plate under mechanical, thermal, and electric loadings combined.

• Transactions of the Korean Society of Mechanical Engineers
• /
• v.16 no.9
• /
• pp.1736-1743
• /
• 1992

The combustion in the cylinder of spark ignition engine is completed after the delayed time that the liquid film fuel is vapourized as flowing into the combustion chamber. It is necessary to enhance the homogeneity of mixture and the combustion phenomenon in order to improve the heat efficiency and the emission characteristics of spark ignition engine. The main purpose of this paper is to manufacture a combustion analyzing system and examine closely the influence of non-uniformity due to the liquid film fuel flowing in the intake manifold on the combustion characteristics by using a 4 stroke multi- cylinder spark ignition engine. Moreover, with each cylinder, the interpretation of combustion characteristics by indicator diagram and the concentration of exhaust gas were investigated.

• Proceedings of the KIEE Conference
• /
• 2002.07b
• /
• pp.709-711
• /
• 2002

The Induction heating is used in various industry and ever-increasing number of applications. The heating roll, which is a kind of induction heating, widely used in curing of coatings and fiber industry. In this papaer, we analized thermal characteristic of induction heating roll by threedimensional eddy-current analysis. Using this analytic results, We could predict the thermal distribution of induction heating roll