• Journal of the Korean Society for Nondestructive Testing
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• v.29 no.6
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• pp.563-569
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• 2009

In this paper, four different types of pulsed eddy current(PEC) probe are designed and their performance of detecting wall thickness reduction is compared. By using the backward difference method in time and the finite element method in space, PEC signals from various thickness and materials are numerically calculated and three features of the signal are selected. Since PEC signals and features are obtained by various types and sizes of probe, the comparison is made through the normalized features which reflect the sensitivity of the feature to thickness reduction. The normalized features indicate that the shielded reflection probe provides the best sensitivity to wall thickness reduction for all three signal features. Results show that the best sensitivity to thickness reduction can be achieved by the peak value, but also suggest that the time to peak can be a good candidate because of its linear relationship with the thickness variation.

• Journal of the Korean Ceramic Society
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• v.45 no.9
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• pp.556-560
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• 2008

The effects of Nb and Co ion substitution on the dielectric and magnetic properties of the multiferroic $BiFeO_3$ thin films have been investigated. Heteroepitaxial $BiFeO_3$ thin films were deposited by Pulsed Laser Deposition method. Nb substitution decreased the leakage current by 6 orders of magnitude and Co substituted $BiFeO_3$ thin films showed an enhanced magnetization, 2 times larger than that of un-substituted $BiFeO_3$. Through the co-substitution of Co and Nb, $BiFeO_3$ thin films with a low leakage current and an enhanced magnetization could be obtained.

• Proceedings of the KIEE Conference
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• 2008.04c
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• pp.53-55
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• 2008

복합층에서 나타나는 투과형 펄스와전류(Pulsed Eddy Current; PEC) 탐상신호를 수치해석 방법을 사용하여 예측하고 분석하였다. 공기층이 없는 복합층에서 Ti-6Al-4V의 두께가 변하는 경우에는 Lift-off를 변화시켰을 때 나타나는 펄스와전류 신호특성과 LOI(Lift-off Intersection)가 형성되는 것을 관찰할 수 있었고, Aluminum의 두께가 변하는 경우에는 Aluminum만의 두께변화 시 발생하던 신호특성이 났다. 공기층이 있는 복합층에서는 Lift-off를 변화시켰을 때 나타나는 신호특성과 LOI가 형성되었고, 공기층이 증가하면 피크 값이 감소하는 것을 볼 수 있었다.

• Proceedings of the KIEE Conference
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• 2001.07b
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• pp.939-941
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• 2001

An efficient control method of ZVS Full-bridge PWM converter with a periodic pulsed-load current is proposed. This novel control method can reduce the switching loss of switches during no load condition. Moreover, by using feed-forwarded load current information this method can obtain better transient dynamics compared to the system with only linear feedback control.

• Journal of information and communication convergence engineering
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• v.6 no.1
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• pp.73-79
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• 2008

Result that study magnet nerve curer for treatment induced current generation and current of ion for development in main point incontinence, prostate, sphincter, nervous system, rigidity, headache, retrogression arthritis, ligament damage, Rheumatism arthritis, peripheral nerve etc., can classify by 4. Embodied do first, full bridge magnet occurrence chapter, and communication with PC is available, confirmed various action loops an experiment. Could confirm correct treatment probe second, woman and man disease person. Third, derived so that healing may be possible naturally by addition of apron form according to disease. Because composition of finally, treatment probe composes by act of negative plate form, manufacture is easy and cooling designed for easy direction. More superior result of cooling appeared than existing in incidental and ingredients, cooling efficiency, composition, complexity, convenience etc. that expense and composition manufacture very straightforwardly and experimental by 2 - Tank ways.

• Proceedings of the KIEE Conference
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• 2002.07c
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• pp.1853-1855
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• 2002

A pulsed Nd:YAG laser is used widely in many applications such as materials processing, communications, military and medical instruments. It is important to control the laser energy in those fields with using a pulsed Nd:YAG laser. In this paper, constant-frequency current resonant half-bridge inverter and feedback control circuit are used to have output stable. This laser power supply is designed and fabri which was isolated. Also, this study is used an one-chip microprocessor, SCR, current transform A stable output of this Nd:YAG laser system investigated. The tested results are described.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.13 no.1
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• pp.28-32
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• 2000

Structural and electrical properties of (Ba, Sr)TiO\ulcorner (BST) thin films prepared by pulsed laser depositon were investigated to verify the influences of post-annealing in oxygen ambient. Increase of post-anneal-ing time in oxygen ambient resulted in not only grain growth but also improvement of crystallinity of BST films. Although the post-annealing in oxygen ambient resulted in the increase of surface roughness, it assisted the dielectric constant increase by eliminating oxygen vacancies. The electrical property enhancement including high dielectric constant and low leakage current density was associated with introducing high pressure of oxygen during the post-annealing.

• Proceedings of the KIEE Conference
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• 1999.07e
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• pp.2239-2241
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• 1999

The most important question is how to use which kind of switch in pulsed power generation. There are many kinds of commercial closing switches, which have advantages and disadvantages. The most popular closing switch is the spark gap, but it has a disadvantage in life time, because of erosion of electrodes by arc heating. The Rotary Arc Gap (RAG) switch, especially Walkie-Edgar type RAG switch, was proposed to solve such problems in spark gap. It has a simple and special structure for arc moving caused from self-induced electromagnetic force, because moving arc makes less erosion on the electrodes. In this study we have made an Walkie-Edgar type RAG switch, tested the switching with capacitive energy storage system, and measured rotating arc speed in different peak current.

• The Journal of Korean Physical Therapy
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• v.7 no.1
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• pp.1-8
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• 1995

The purpose of this study was to determine the effects of high voltage pulsed current(HVPC) and low voltage pulsed current(LVPC) on posttraumatic edema formation in frog hind limbs In this study, 16 bullfrogs(Rana Catesbeiana), weighting 189g to 340g were used. Limb 16 anesthetized bullfrogs were systemically injuried by weight drop. One hind limb of each frogs was randomly selected to receive continuous 120 pps HVPC and 100 pps LVPC at $90\%$ of motor threshold(HVPC : 33.3v, LVPC : 0.2-1mA). The opposite hind was remained as a control. A series of six 30-minute treatment(interrupted by 30-minute rest) was begun minutes after injury. The results were as follows. 1. Cathodal HVPC has heed shown to be effective in curbing posttraumatic edema formation in frogs, but anodal HVPC did not effect. 2. Volumes of hind limbs treated with LVPC were not significantly different over time from those of untreated hind limbs. 3. Therefore, waveform(HVPC versus LVPC) seems to influence the efficacy of electrotherapy for edema control. 4. Electrical stimulation were not increased edema formation on frog hind limbs.

• Corrosion Science and Technology
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• v.9 no.1
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• pp.8-11
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• 2010

During PEO (plasma-electrolytic-oxidation) treatment of titanium, the relationship between the thickness of oxide film and the measured electrical information was investigated. A simple real time monitoring method based on the electrical information being gathered during PEO treatment is proposed. The proposed method utilizes the current flowing from a high frequency voltage source to calculate the resistance of an oxide film, which is converted into the thickness of an oxide film. This monitoring method can be implemented in PEO system in which an oxide film is grown by constant or pulsed voltage/current sources.