• Proceedings of the KIEE Conference
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• 1998.07e
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• pp.1644-1646
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• 1998

High-Smokestacks have been the symbol of the thermal power plant. Those cause the thermal power plant to be damaged by lightening for reaching several hundreds meter. In this paper, we investigated the accident of low-voltage source circuit due to grounding potential rise by lightening via high-smokestack in practically driving power plant, described examination into the cause and the impulse analysis. We analysed the transient voltage by EMTP(ElectroMagnetic Transient Program) via modeling the grounding system of power plant. This theoretical results coincided with practical accidental state. Therefore, it was verified that we could apply the grounding system of power plant and substation with the distribution-circuit analysis(EMTP).

• Journal of the Korean Institute of Telematics and Electronics
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• v.4 no.3
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• pp.28-33
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• 1967

The analysis of differential amplifier is simplified by the extention of bisection theorem. In order to reduce the thermal and porwor drifts, a self compensating circuit is employed. The optimum conditions of the self compensating circuit are: the base-emitter voltage of one transistor should be equal to the other's base-emitter voltage for basic self compensating circuit, the tempereature coefficients of base-emitter voltage of one transistor equal to the others for thermal compensation. By regarding the thermal and power drifts the experiments were performed were performed and the numerical results were consistent with the measured values.

• Journal of the Microelectronics and Packaging Society
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• v.19 no.3
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• pp.49-56
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• 2012

Recently, by the trends of electronic package to be smaller, thinner and more integrative, fine bump is required. but It can result in the electrical short by reduced cross-section of UBM and diameter of bump. Especially, the formation of IMCs and KV can have a significant affects about electrical and mechanical properties. In this paper, we analyzed the thermal deformation of flip-chip bump by using FEM. Through Thermal Cycling Test (TCT) of flip-chip package, We analyzed the properties of the thermal deformation. and We confirmed that the thermal deformation of the bump can have a significant impact on the driving system. So we selected IMCs thickness and bump diameter as variable which is expected to have implications for characteristics of thermal deformation. and we performed analysis of temperature, thermal stress and thermal deformation. Then we investigated the cause of the IMC's effects.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.61 no.10
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• pp.1420-1425
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• 2012

Nowadays, Interior permanent magnet synchronous motor(IPMSM) which having high power density is much used for the vehicles. However, IPMSM causes a lot of losses because of high-speed driving and high current density, and temperature rising by iron loss and copper loss could reduce torque characteristics and durability of IPMSM. Therefore, analysis about thermal characteristics of IPMSM is required at design stage. In this paper, temperature characteristics according to current vector control method were analyzed through calculate thermal equivalent circuit. And calculated results were verified through comparing with the experiments.

• Journal of the Korean Institute of Telematics and Electronics S
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• v.35S no.1
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• pp.122-129
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• 1998

For generation and analysis of the multi-sensory image, we propose a new three dimensional (3D) modeling method considering an iternal heat source. We represent the heat conduction process within th object as an equivalent thermal circuit. Therefore, without a complex computation, our modeling approach can obtain thermal features of the object. By using the faceted model, the proposed method can express the accurate visual signatures of the object. Comparing the estimates datum with the obtained surface temperatures, we have demonstrated that the proposed method can provide a precise thermal features. The thermal images by out model is applicable to simulate a tracking loop of an IR missile.

• Journal of Electrical Engineering and Technology
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• v.9 no.3
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• pp.893-898
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• 2014

Recently, the interior permanent synchronous motor (IPMSM) has been applied to an integrated starter and generator (ISG) for hybrid electric vehicles. In the design of such a motor, thermal analysis is necessary to maximize the power density because the loss is proportional to the power of a motor. Therefore, a cooling device as a heat sink is required internally. Generally, a cooling system designed with a water jacket structure is widely used for electric motors because it has advantages of simple structure and cooling effectiveness. An effective approach to analyze an electric machine with a water jacket is a thermal equivalent network. This network is composed of thermal resistance, a heat source, and thermal capacitance that consider the conduction, convection, and radiation. In particular, modeling of the cooling channel in a network is challenging owing to the flow of the coolant. In this paper, temperature prediction using a thermal equivalent network is performed in an ISG that has a water cooled system. Then, an experiment is conducted to verify the thermal equivalent network.

• Nuclear Engineering and Technology
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• v.55 no.10
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• pp.3860-3865
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• 2023

A metallic microcell UO₂ pellet has a microstructure where a metal wall is connected to overcome the low thermal conductivity of the UO₂ fuel pellet. It has been verified that metallic microcell fuel pellets provide an impressive reduction of the fuel centerline temperature through a Halden irradiation test. However, it is difficult to predict the effective thermal conductivity of these pellets and researchers have had to rely on measurement and use of the finite element method. In this study, we designed a unit microcell model using a thermal resistance circuit to calculate the effective thermal conductivity on the basis of the microstructure characteristics by using the aspect ratio and compared the results with those of reported metallic UO₂ microcell pellets. In particular, using the thermal conductivity calculated by our model, the fuel centerline temperature of Cr microcell pellets on the 5th day of the Halden irradiation test was predicted within 6% error from the measured value.

• Journal of East-West Nursing Research
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• v.26 no.2
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• pp.149-156
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• 2020

Purpose: The purpose of this study was to identify the effects of the heated-humidified breathing circuit applied on the body temperature, shivering, and thermal comfort of general anesthesia patients. Methods: The participants were patients who received general anesthesia at University Hospital K located in City B, with 25 patients in the experimental group and 25 patients in the control group. The period of this study was from Mar 19 to Apr 26, 2019. The experimental equipment included a heated-humidified breathing circuit, which connects the intubation tube with the anesthesia machine for mechanical ventilation after airway intubation in general anesthesia patients. Results: The body temperature, shivering, and thermal comfort after surgery were significantly different between the two groups (p<.001). However, the body temperature during surgery was slightly different between the experimental group and the control group. Conclusion: A heated-humidified breathing circuit may be actively used in a warming method to prevent the hypothermia of general anesthesia patients.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.25 no.9
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• pp.75-79
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• 2011

The MOV(Metal Oxide Varistor), a voltage limiting element, has been installed in the SPD(Surge Protective Device) or inside the internal circuit of an electronic appliance for protection of the electric power system and electronic device against electrical surge. Such an MOV is exposed, however, to the risk of the thermal runaway resulting from excessive voltage and deterioration. In this paper, a reciprocal action has been tested and analyzed using a phosphorus bronze switching module and the low-temperature solder. And a short current break characteristic test linked with the circuit breaker has been performed to limit the inrush current when the MOV breaks down. It has been proven that the phosphorus bronze switching module installed inside the internal circuit can improve the safety of the power line system and the electronic device.

• Proceedings of the KIEE Conference
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• 1994.07b
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• pp.1603-1605
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• 1994

Recently, Gas Circuit Breakers are rapidly replacing Vacuum Circuit Breakers in the medium voltage switchgear. This is due to the improved performance of - GCB in interrupting capability, price, weight, size etc., while the countermeasure to suppress the switching surges of VCB has not been satisfactory. Intensive research works on the GCB have been conducted in the world widely since 1980. Nowadays it is well known that the thermal expansion type GCB can provide- better performance than puffer type in the distribution power system. KERI has conducted researches in the GCB rated at 25.8kV 25kA with Jinkwang Co. using the thermal expantion principle since 1993. In this paper, the calculated results of electric and magnetic fields for the model GCB are presented and analyzed. The effect of permanent magnet used to improve the interruption capabilty at the low current level is also investigated. The design parameters for the interrupter inspected through the short-circuit tests conducted at high power laboratory of KERI.