• Proceedings of the KIEE Conference
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• 2005.07c
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• pp.2250-2252
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• 2005

본 논문은 HVDC용 크라프트 절연지의 기본 전기적 특성평가를 목적으로 온도별 역률의 변화, 절연저항 및 임펄스 절연파괴강도 등을 측정한 결과이다. 온도에 따른 크라프트 절연지의 역률은 $50{\sim}70^{\circ}C$에서 최소 값을 나타내었으며, 밀도가 낮은 시료일수록 낮은 역률을 나타내었다. 하지만, 임펄스 절연파괴 강도는 밀도가 낮을수록 저하되는 특성을 나타내어 적절한 밀도의 선정이 필요하다는 사실을 알았다. 또한, 온도 및 인가 전계에 따른 절연저항을 측정하여 크라프트 절연지의 온도상수 및 전계상수를 측정한 결과, 온도상수 ${\alpha}$는 $0.09{\sim}0.1^{\circ}C^{-1}$, 전계상수는 약 1.5을 얻었다. 이는 HVDC용 케이블의 설계 시 절연체의 전계분포 및 두께 산정에 기본적인 데이터를 제공할 수 있다.

• Fire Science and Engineering
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• v.13 no.2
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• pp.12-17
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• 1999

We intended to investigate combustion properties of rice bran dust. Combustion properties of h rice bran dust according to size distribution and amount were measured as temperature v variation with time using spontaneous ignition apparatus. Moreover, combustion properties w with blowing or without blowing condition were checked in order to investigate combustion p properties in spontaneous ignition apparatus according to flow condition of air. A As the mass and size of rice bran dust was increased, i띠ti외 smoldering temperature was l lowered. All of combustion forms were smoldering combustion. Initial smold얹ing temperature w was slightly lower with blowing condition than without blowing condition in spontaneous i ignition apparatus, which condition made heating value high.

• Journal of the Korean Vacuum Society
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• v.20 no.4
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• pp.307-312
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• 2011

As a technique for removing cancerous tumors from normal tissue, radio-frequency electromagnetic waves were employed to heating target cells up to the critical temperature, which kills the cancerous cells. However, its use in treating tumors in soft organs is limited by inconvenient factors, which are use of high-currents and long time operation. In this work, the feasibility of the localized heating by inserting four conducting electrodes with tiny direct current is investigated. The heat source is resulting from the electric field as known as resistive heating. We have investigated the temperature distribution as a function of applying DC voltages ranging from 10 V to 30 V with 10 V step. From the simulation results, the mushroom-like lesion shape by applying 20 V is generated by four electrodes within a few minutes, that is proper to the clinical application.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.3
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• pp.83-89
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• 2018

The thermal characteristics of concrete specimens were analyzed using cement paste specimens with artificial cracks. In order to understand the temperature characteristics of the specimen depending on the crack depth, the specimen was heated and the minimum temperatures of the specimens at which cracks appear were investigated according to the crack depth. It was confirmed that the surface temperature distribution of the specimen varies depending on whether the specimen is cracked or not, because of the single and multiple reflections of the incident energy. Furthermore, as the temperature distribution of the specimen reaches a steady state, the temperature data tends to decrease with the crack depth. Through the observation of the normalized temperatures, it was found that the temperature of the specimens obtained from this experiment reached a steady state after 10 minutes. At this time, the standard deviation of the normalized temperature is around 0.01 or less, and the temperature decreases linearly with increasing crack depth. This result is considered to be closely related to the area where multiple reflections occur in the cracked region. If the correlation between the crack region and the incident energy is analyzed for various specimens, it can be applied to the diffuse reflection of the light.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.10
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• pp.4398-4404
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• 2012

This thesis was conducted a numerical analysis on the radiant heat performance according to factors of design of heat sink for cooling of the automotive LED head lamp. The heat sinks were designed with 5 different types to fit the limited internal space by formula based on an existing product (Type 1). Designed heat sinks of five types were analyzed by ANSYS CFD V12.1, and the analysis results were compared with the existing type. The results of simulation were analyzed temperature distribution and average temperature, air flow characteristic, heat flux etc. This thesis was researched on the correlation of the cooling performance according to the heat sink structure and the fin shape. Through numerical analysis, could be confirmed heat sink Type 2 as the best results.

• Korean Journal of Remote Sensing
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• v.20 no.2
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• pp.103-116
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• 2004

The mesoscale atmospheric models to produce surface temperature can not generally consider the effect of the sloped terrain for direct solar radiation. These have not showed the regional difference of solar radiation and as a result, have made the big error in the local surface temperature. Therefore, we wished to represent the exact locality of surface temperature by considering the geometric properties of surface as well as the vegetated properties of surface. The purpose of the study is to produce local surface ground temperature in sloped terrain diagnostically using surface Energy Balance Model (EBM) with the use of GRID model in Geographic Information Systems (GIS). In this study, surface inhomogeneity over southeastern part of Korean peninsula are considered in estimation of the absorbed surface solar radiation in terms of the illumination angle, depending on topographical aspect and slope in GRID. Also, the properties of vegetated surface which the major components for the variability of surface temperature are considered in terms of NDVI. The results of our study show the locally changes in the surface ground temperature due to local ground aspect and slope effect and local properties of vegetated surface. The more detailed distribution of local surface temperature may drive the local circulation at lower atmospheric and it may explain better the real local circulation.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2011.11a
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• pp.283-291
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• 2011

A computational investigation has been carried out to study the heat transfer characteristics of jet vane assembly used for the thrust vector control(TVC) of a vertical launch motor. In this study, the coefficients of convective heat transfer on the jet vane are calculated using the solutions of thermal boundary-layer equation and several semi-empirical equations. The calculation of 3-dimensional temperature distribution for the jet vane assembly was performed using the softwares called PATRAN and ABAQUS. The accuracy of the present numerical method is verified by comparing with the measured and calculated temperatures within jet vane shaft. The temporal variation of jet vane temperatures for three deflection angles(0o, 12.5o, 25o) was discussed.

• Journal of Power System Engineering
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• v.3 no.1
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• pp.16-22
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• 1999

The purpose of this study is to prevent the stick, scuffing, scratch between piston and cylinder, is to contribute the piston design such as piston profile, clearance by calculating reaction force by over-lap of piston skirt, as measuring the temperature distributions of cylinder wall. The experiment has been peformed to obtain data during actual engine operation. Temperature gradient in peripheral and axial distributions of cylinder wall according to torque and speed of engine were measured by use of an 800cc class gasoline engine. The results obtained are summarized as follows ; 1) The temperature of cylinder wall at TDC was about $50{\sim}75^{\circ}C$ higher than temperature of cooling water. 2) The rear side temperature of top dead center was $141^{\circ}C$(1/4 load) in axial distribution, whereas the rear side of midway position temperature was $98^{\circ}C$. 3) The temperature of cylinder wall increased in according to rising temperature of cooling water. 4) The thrust side temperature of cylinder wall was about $15^{\circ}C$ in all load test. 5) The rear side temperature of top dead center was $159^{\circ}C$ (1/2 load) in peripheral distribution, it was about $39^{\circ}C$ higher than thrust side temperature.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.13 no.3
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• pp.34-39
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• 1999

Electron temperature and electron density were rreasured in a radio-frequency inductively coupled plasma (RFICP) using a Langmuir probe method. Measurerrent was conducted in an argon discharge for pressures from 10 mTorr to 40 mTorr and input rf rnwer from 100 W to 600 W. Spatial distribution electroo temperature and electron density were rreasured for discharge with satre aspect ratio (R/L=2). Electron temperature and electron density were discovered depending on both pressure and power. Electron density was increased with iocreasing input power, but saturated at 450 W. Electron density was iocreased with iocreasing pressure. Radial distribution of the electron density was peaked at the rnsition which was a little rmved from center toward quartz window. Normal distribution of the electron density was peaked in the center between quartz plate and substrate. The above results could contribute to understand the Mechanism of Radio-Frequency Inductively Discharge Plasma.Plasma.

• Journal of Korean Society for Geospatial Information Science
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• v.1 no.2 s.2
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• pp.185-194
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• 1993

In this research, the image obtained by TM platformed in the LANDSAT-5 and the terrestrial infrared image obtained by the Thermo Tracer were employed in order to search the distribution of industrial thermal plume discharged into seas. Sea surface temperature distributions were deduced based on the infrared band 6 in the TM image of the LANDSAT by employing the transformal formula provided by the CSFC of the NASA and post-calibration values. The temperature distributions were also obtained with the processing mode of the TH1100 series from the terrestrial thermal image or the Thermo tracer. According to the results of the image analyses with this methods, it was found that sea surface temperatures in shallow coastal area largely affected by the temperatures of the freshwater and inland and that the range and the area of distribution of the thermal plume can be visualized quantitatively. Furthermore, when the terrestrial thermal infrared scanner is used, the more details of the distribution range can be obtained, and the image results are comparable to those obtained from the LNADSTA.