• Journal of the Korean Society for Nondestructive Testing
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• v.36 no.3
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• pp.202-210
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• 2016

A thermal barrier coating (TBC) has been widely applied to machine components working under high temperature as a thermal insulator owing to its critical financial and safety benefits to the industry. However, the nondestructive evaluation of TBC damage is not easy since sensing of the microscopic change that occurs on the TBC is required during an evaluation. We designed an eddy current probe for evaluating damage on a TBC based on the finite element method (FEM) and validated its performance through an experiment. An FEM analysis predicted the sensitivity of the probe, showing that impedance change increases as the TBC thermally degrades. In addition, the effect of the magnetic shield concentrating magnetic flux density was also observed. Finally, experimental validation showed good agreement with the simulation result.

• Journal of Pharmaceutical Investigation
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• v.31 no.2
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• pp.107-112
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• 2001

In order to reduce the systemic side effects and gastrointestinal irritation after its oral adminitration, ketoprofen was formulated as water-soluble packs. The effects of fatty acids and fatty alcohols on the penetration of ketoprofen through excised rat skins were evaluated. The role of stratum corneum as a protective barrier was also investigated. Fatty acids and fatty alcohols were generally effective in promoting ketoprofen penetration. The flux of ketoprofen through rat skin was maximized when oleic acid or lauryl alcohol was used as an enhancer. As the concentration of fatty acids and fatty alcohols varied from 0% to 10%, the amounts of ketoprofen penetrated were in direct proportion to that of fatty acids but those had no relationship with that of fatty alcohols. The penetration of ketoprofen through stripped skin was enhanced compared to normal skin irrespective of enhancer type, which indicated that the action site of enhancers would be stratum corneum.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.56 no.3
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• pp.519-523
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• 2007

In this paper, we propose a precise parameter extraction of interior permanent magnet (IPM) motors based on finite element analysis. For the calculation of the two-axis inductances Ld and Lq, the slotting effect and cross magnetization due to torque angle are considered. It is examined that back electro-motive force (BEMF) constant is affected by the magnetic saturation in different ways dependent on motor types. Numerical analyses and some measurements are performed for a spoke type and a flux barrier type IPM motors

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.867_868
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• 2009

Interior permanent magnet synchronous motor [IPMSM] which has high power density is applied to motor for Hybrid electric vehicle[HEV], Electric vehicle[EV], Fuel cell electric vehicle[FCEV] and electric home appliances. In order to improve efficiency performance of IPMSM, this paper presented a study by making a hole around air barrier. Because concentrated rib stress is distributed by suitable hole, the hole can reduce rib thickness of IPM rotor. And it can help decrease PM[Permanent Magnet] leakage flux. Saliency ratio($L_q/L_d$) is also increased by magnetic circuit change. For this study, structure analysis of rotor is performed by Ansys program.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.57 no.10
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• pp.1777-1781
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• 2008

This paper deals with optimum design criteria for maximum torque density & minimum torque ripple of Synchronous Reluctance Motor (SynRM) according to the rated wattage using response surface methodology (RSM). The RSM has been achieved to use the experimental design method in combination with Finite Element Method and well adapted to make analytical model for a complex problem considering of a number of interaction of design variables. The proposed procedure allows the definition of the rotor shape according to flux barrier number, starting from an existing motor or a preliminary design.

• Journal of Pharmaceutical Investigation
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• v.25 no.3
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• pp.53-59
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• 1995

Ethinylestradiol (EE)-containing matrix was fabricated with ethylene-vinyl acetate(EVA) copolymer to control the release of the drug, Effect of addition of PEG 400 as receptor solution, the stripping of skin and Azone pretreatment on skin on the permeation of EE through the excised mouse skin was also studied. The permeation rate of EE through the excised mouse skin was affected by the PEG 400 volume fraction. The Azone pretreatment on skin didn't affect on the steady state flux, however, the lag time was shortened. The permeation rate of EE through the stripped skin was much larger than that through the whole skin. It showed that the stratum corneum acts as a barrier of skin permeation. The fact that there is little difference in EE permeation between the intact skin and the stripped skin with EVA membrane shows the permeation of EE through the mouse skin is mainly controlled by the membrane.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.814-815
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• 2008

매입형 영구자석 동기전동기의 경우 고효율, 고출력 그리고 넓은 속도 범위와 같은 많은 장점에도 불구하고 상대적으로 큰 코깅토크와 토크 리플로 인하여 정밀한 위치 제어용 전동기로 사용하는데 있어 한계가 있다. 이는 flux barrier와 치 사이의 불연속적인 자기저항의 변화가 주요한 원인 중의 하나로 이를 최소화 할 수 있는 형상 설계가 필요하다. 따라서 본 논문에서는 초기 설계된 매입형 영구자석 동기 전동기의 특성을 향상시키기 위한 형상 설계를 제시하고 실험 결과를 통하여 제안된 설계 방법의 유용성을 증명하고자 한다.

• Proceedings of the KIEE Conference
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• 1997.07a
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• pp.300-302
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• 1997

Synchronous Reluctance Motors(SynRM) with multiple flux barrier structures are considered in this paper. Since the stator of a SynRM is similar as that of an inductin motor, attention is focused here on the rotor structure. We have designed the parameter of SynRM and analyzed the characteristics of the electromagnetic energy conversion.

• Journal of international Conference on Electrical Machines and Systems
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• v.2 no.2
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• pp.141-147
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• 2013

Permanent magnet (PM) motors that employ rare-earth magnets containing dysprosium (Dy) are used in electric and hybrid electric vehicles. However, it is desirable to reduce the amount of Dy used since it is expensive. This study investigates the rotor structure of a PM synchronous motor with a Dy-free rare-earth magnet. Flux barrier shapes and PM thicknesses that enhance the irreversible demagnetization are investigated. In addition, a rotor structure that improves the irreversible demagnetization is proposed. We demonstrate that the proposed rotor structure without Dy improves the irreversible demagnetization.

• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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• v.11B no.2
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• pp.1-8
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• 2001

This paper deals with magnetic field analysis and computation of cogging torque using an analytical method in Interior Permanent Magnet Motor (IPMM). The magnetic field is analyzed by solving space harmonics field analysis due to magnetizing and the cogging torque is analyzed by combining field analysis with relative permeance. In reducing cogging torque, the inferences of various design variable and magnetizing distribution are investigated. It is shown that the slot and pole ratio (the pole-arc / pole-pitch ratio) combination has a significant effect on the cogging torque and presents a optimal flux barrier shape to reduce the cogging torque. The validity of the proposed technique is confirmed with 2-D Finite Element(FE) analysis.