• Journal of the Korea Academia-Industrial cooperation Society
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• v.9 no.3
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• pp.599-604
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• 2008

An experimental study has been performed to investigate the air-side capacity and pressure drop of the fin-tube heat exchanger for a fan coil unit under a cooling condition. The experimental data of five kinds of slit fin-tube heat exchangers were measured using an air-enthalpy calorimeter and a constant temperature water bath. Cooling capacities at the air and water rating flow rates were larger at the lower inlet water temperature. With increasing the water flow rate, the cooling capacity increased at the constant rate. Under the lower inlet water temperature, since the condensate was generated more on the fin-tube surface, the air-side pressure drop of the heat exchanger was larger.

• Proceedings of the KIEE Conference
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• 1996.07c
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• pp.1479-1481
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• 1996

The Purpose of this paper is to produce air core inductor and measure its electrical properties for high frequency. Especially we focused attention on the effect of geometrical parameters such as coil width, distance between coils, turn number. In addition, the influence of film morphology at inductor was investigated. Increase of coil width and decrease of turn number resulted in promotion of electric properties.

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2001.11a
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• pp.333-334
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• 2001

대기 중 포름 알데하이드 연구의 중요한 이유는 인체에 대한 악영향을 끼치는 화합물이라는 점과 대기 중 거의 모든 유기화합물들의 광산화 반응 1차 생성물인 카르보닐 화합물 가운데 가장 풍부하게 존재하고 라디칼의 중요한 기원자로 작용하기 때문이다. 인체에 대한 악영향의 현상으로는 눈, 코, 목을 자극하고 기관지 천식, 피부 알레르기를 유발시키는 것으로 나타나고 최근에는 동물과 인간의 발암물질로도 확인되어지고 있다. (중략)

• Journal of Magnetics
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• v.15 no.3
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• pp.143-147
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• 2010

Rotary-type voice coil motors are widely used as actuators in hard disk drives. The recent trend toward higher density and smaller form factors in data storage devices requires performance improvement of the voice coil motor. In this study, we introduce a Halbach magnet array to the voice coil motor in order to increase the force generation. The Halbach magnetic circuit outperforms the conventional magnetic circuit due to the confined magnetic flux. To investigate the performance of the Halbach magnetic circuit, we analyze air gap flux density with the various shapes and thickness of the magnets using 3-dimensional finite element analysis. Consequently the optimum shape of the Halbach magnetic circuit is proposed. Simulations and experimental results proved effectiveness of the proposed magnet array in the voice coil motor for a commercial hard disk drive.

• Journal of the Korean Magnetics Society
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• v.26 no.2
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• pp.62-66
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• 2016

We designed a model composed a ring type magnet, a yoke, and a sensing coil buried in a projectile for calculating the muzzle velocity based on the voltage induced from sensing coil by simulation. The muzzle velocity was calculated from the master curve obtained through the voltage induced from sensing coil by simulation. The induced voltage increased with increasing the diameter of sensing coil. The projectile's velocity was proportional to the induced voltage when the sensing coil was buried in projectile. The projectile will be surely exploded at the target region by inputting the information of muzzle velocity variation corrected the diameter effect of induced voltage of sensing coil.

• Proceedings of the KIEE Conference
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• 1994.07a
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• pp.125-128
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• 1994

One of the abnormal motions of the projectile in the coil gun is spinning. It is found that the spinning force is closely related with air gap distance. Modified and detail analysis for the spinning is suggested in this paper. Two reasons for spinning force and Lorentz force affecting on the spinning are introduced. Nutation, which is a result of spinning, is explained there after.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1997.11a
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• pp.350-355
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• 1997

A new magnetic field measuring system with induced coil is reported. This system consists of air-cared coil that is forced by the ultrasonic transducer. Induction voltage of coil is proportional to the DC magnetic field and the driving frequency of ultrasonic transducer by the principle of Faraday's law. The experimental measuring system is setup, and the possibility of a new magnetic field sensors is confirmed.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.11 no.3
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• pp.339-348
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• 1999

A computer model was developed in order to predict the temperature distribution and the performance of the vertical tube-in-tube ground coil heat exchanger. This model has been validated by experimental results conducted by ORNL. The heat exchanger performance with the variation of the length is calculated and compared. As results, the heat exchanger performance is proportional to the length but the performance per unit length decreases. The minimum performance of 70m - PVC heat exchanger during cyclic operation for a week is obtained 20,054kJ/h for cooling operation and 13,915kJ/h for heating operation. And minimum temperature difference is $4.64^{\circ}C$ for cooling operation and $2.64^{\circ}C$ for heating operation. In each case, it is noted that the temperature difference between the pipe and the far-field occurs within 0.8m from the heat exchanger.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.23 no.11
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• pp.762-768
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• 2011

We use floor radiant heating system in the house of commons in winter Floor radiant heating system, which transfer heat by radiation, is one of the energy efficient and comfortable systems that. Floor radiant heating system is configured to be controlled by the room for energy-saving. Proper flow rate to a comfortable heating in the room is important. However, Using a constant speed circulation pump in separate rooms, heating system may cause an imbalance because of the difference of length of coil when operating in the rooms. In this study, our Research team examined heating imbalance due to the variation length through the coil length changes and flow control of the circulation pump.

• Proceedings of the KIPE Conference
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• 2015.11a
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• pp.27-28
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• 2015

In this paper a high efficiency wireless on-board charger for Electric Vehicle (EV) is proposed and the theoretical analysis based on the two-port network model to come up with suitable design for the battery charge application is presented. The proposed Wireless Power Transfer (WPT) method has adopted four-coil system with air core and its superior performance is proved by comparing it to the conventional two-coil system by the mathematical analysis. In addition, since the proposed WPT converter is able to operate at an almost constant frequency regardless of the load, CC/CV charge of the battery can be simply implemented. A 6.6kW prototype is implemented with 20cm air gap to prove the validity of the proposed method. The experimental results show that the dc to dc conversion efficiency of the proposed system achieves 97.08% at 3.7 kW.