• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.05a
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• pp.193-196
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• 2005

유기발광소자의 발광층의 두께에 따른 임피던스의 변화를 살펴보았다. 임피던스는 두께에 따라 저항의 변화에 따른 의존성을 보이며, 그에 따른 임피던스와 Cole-Cole 반원의 변화, 두께에 따른 $1/\tau$ 의 변화를 살펴보았다. 발광층의 두께는 각각 100, 200, 300 nm의 두께로 열증착하여 실험하였고, 소자의 구조는 $ITO/Alq_3/Al$의 구조로 측정 하였다. 유기발광소자의 발광층인 $Alq_3$의 두께가 증가함에 따라 임피던스의 크기가 증가하고, 위상각의 크기는 100nm의 경우 0V에서 용량성을 보이다가 6~10V까지 부성저항특성을 나타낸 후 약 22V에서 저항성을 나타내고, 200과 300 nm의 경우 12V까지 용량성을 나타내다 이후 22V 근방에서 $0^{\circ}$에 가까워지며 저항성을 나타내는 것을 알 수 있었다. 또한 두께에 따른 Cole-Cole 반원을 살펴보면 두께가 증가할수록 반원의 크기가 증가하는 것을 알 수 있으며, 이를 통해 간단한 등가회로를 예측할 수 있었다. 그리고 벌크내의 용량성$(C_p)$을 측정하여 두께의 증가에 따라 $C_p$ 값이 감소하는 것을 알 수 있었다.

• Proceedings of the KIEE Conference
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• 2001.04a
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• pp.84-86
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• 2001

This paper deals with the characteristic and thermal analysis of brushless motors for Rack assist type Electric Power Steering(REPS). The performance of permanent magnet is under the influence of temperature. To predict the motor performance, the thermal analysis is necessary. The equivalent thermal network is composed of the thermal resistance and the temperature of major parts is calculated according to the operating condition.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.29 no.1
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• pp.53-60
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• 2016

This study discusses the thermal insulation capacity of variant of NO96 LNG (liquefied natural gas) cargo containment insulation system. Changing the insulation materials and the insulation layers of conventional GTT NO96 containment system, The thermal resistance and BOR(boil off rate) caused by the heat transfer between cryogenic and environmental temperature is discussed. Therefore, thermal analysis of LNG CCS(cargo containment system) is carried out to determine the insulation capabilities. Also, BOR is evaluated in terms of the total amount of heat invaded into CCS(cargo containment system). Variant of NO96 CCS such as NO96, NO96GW and NO96L3 membrane type during laden voyage is selected for the comparative study. Finite element model for heat transfer analysis is conducted by employing the equivalent thermal resistance model to simplify the complex insulation layers. Finally the results for each variant model are relatively compared and discussed to minimize the BOR.

• Journal of the Korean Society for Geothermal and Hydrothermal Energy
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• v.12 no.4
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• pp.21-26
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• 2016

In this study, the control strategies of indoor air temperature in floor radiant heating system were researched by computer simulation. The temperature difference based time control method using the difference of indoor set temperature and indoor temperature is compared with the existing On-Off control one for heating control performances. As a result, the temperature difference based time control method shows better thermal environmental characteristics in case of selected operational conditions in comparison with existing control one.

• Proceedings of the SAREK Conference
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• 2007.11a
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• pp.52-57
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• 2007

The control characteristics for radiant panel heating system with automatic thermostatic valves were researched by computer simulation and experiment. The unsteady energy analysis using equivalent R-C circuit method and radiation heat transfer analysis of enclosure analysis method with simple structured rooms was performed. The results of flow rate changes of the simulation study are good fit with the ones of experimental one.

• Proceedings of the SAREK Conference
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• 2006.06a
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• pp.927-932
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• 2006

A simulation and experimental study for energy flow dynamics of floor radiant heating system were performed. The study was done under both environmental chamber and a house with several rooms. The unsteady energy analysis method using equivalent R-C circuit and radiation heat transfer analysis of enclosure analysis method with simple structured rooms were used for computer simulation. Also, first order dynamics with time delay in analyzing the return water was considered. The results of temperature changes of the simulation study are good fit with the ones of experimental one.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.21 no.3
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• pp.457-472
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• 1997

We studied the temperature distribution and heat transfer characteristics of TEFC induction motor with thermal network program for more efficient design and better cooling performance of it. We knew the characteristics and the windage loss of outer cooling fan from fan test experiments. Frame axial and peripheral heat transfer coefficients and endwinding heat transfer coefficient were measured by various model experiments and then, compared with other experimental results. Frame was the main heat transfer surface, load-side and fan-side surface were not thermally symmetric from the heat flux distribution analysis. Steady and unsteady temperature distributions were measured by real motor experiments. From the results, we knew that rotor surface temperature was higher than coil temperature and the hottest spot in the coil was loadside endwinding outside surface. We compared the simulation results with those of real motor test and the two results showed a good agreement.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.13 no.12
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• pp.2655-2661
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• 2009

In this paper, an accurate noise parameters for thermal noise modeling of short channel MOSFET is derived and extracted. Fukui model for calculating the noise parameters of a MOSFET is modified by considering effects of parasitic elements in short channel, and it is compared with conventional noise model equation. In addition, for obtaining the intrinsic noise sources of devices, noise parameters(minimum noise figure $F_{min}$, equivalent noise resistance $R_n$ optimized source admittance $Y_{opt}=G_{opt}+B_{opt}$) in submicron MOSFETs is extracted. With this extraction method, the intrinsic noise parameters of MOSFET without effects of probe pad and extrinsic parasitic elements from RF noise measurements can be directly obtained.

• Applied Chemistry for Engineering
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• v.8 no.6
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• pp.1034-1040
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• 1997

Temperature distribution of battery module consists of 11 batteries of 90Ah rate is analyzed using commercial software NISA II. Equivalent thermal resistance network is used to reduce the number of element in calculating heat transfer through a medium composed of several different thermal conductivity layers. Orthotropic model is used to put different thermal conductivity values according to Cartesian coordinate. Aluminum cooling fins are inserted in the middle of batteries to reduce battery module temperature. The cooling fin at the end of the module does not necessary in reducing maximum temperature. Combined effect of front and side cooling fin is analyzed to reduce the temperature difference among batteries. The maximum temperature difference among batteries is reduced within $3^{\circ}C$ when 4 aluminum cooling tin of 1mm thickness is inserted in battery module.

• International Journal of Highway Engineering
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• v.12 no.3
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• pp.1-8
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• 2010

This study is performed to evaluate the physical and mechanical characteristics of an acryl polymer concrete that is developed as an overlay material for cement concrete slabs and pavements. Various laboratory tests including viscosity, flow, compressive strength, flexural strength, tensile strength, linear shrinkage, thermal expansion and thermal compatibility tests are performed. It is observed from the laboratory tests that the acryl polymer concrete developed in this study satisfies all the requirements suggested by ACI guideline. In addition to the laboratory tests, an accelerated performance testing (APT) is conducted to validate the performance of the acryl polymer concrete. During the APT, no significant distresses are observed until 15,903,939 cycles of equivalent single axle loading is applied. Finally, a 10mm thick overlay with the acryl polymer concrete is applied on top of an old deteriorated concrete pavement to evaluate field performance. Right after the field construction, skid resistance, noise and roughness are measured. The skid resistance and noise level have been significantly improved while the roughness is increased. Periodic investigation for the field study section will be conducted to evaluate the long-term performance.