• Journal of rehabilitation welfare engineering & assistive technology
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• v.11 no.1
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• pp.63-71
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• 2017

In this paper, a signal processing circuit for semi-implantable middle ear hearing device is designed using the TCBT which is recently proposed for a new middle ear transducer that can be implanted at round window of cochlea. The designed semi-implantable hearing device transmits digital sound signal from external device located at behind the ear to the internal device implanted under the skin using inductive coupling link methods with high efficiency. The coils and signal processing circuits are designed and implemented considering the total transmission and reception distance including skin thickness of temporal bone for the semi-implantable hearing device. And also, to improve the data transmission efficiency, the output circuits which can supply sufficient signal power is designed. In order to confirm operation of semi-implantable hearing device using inductive coupling link, the circuit analysis was performed using PSpice, and the performance was verified by implementing a signal processing board of an available size.

• Journal of Sensor Science and Technology
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• v.23 no.6
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• pp.409-415
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• 2014

We had presented an inductive type intraocular pressure sensor (L-sensor) in previous work. The distance between a micro coil and a ferrite on the membrane was modulated by pressure, and as a result the inductance and resonant frequency were changed. However, L-sensor has some problems to implant in eyes. First problem is low sensitivity. When L-sensor was implanted in rabbit's eyes, resonant frequency of L-sensor was very hard to detect. Second problem is biocompatibility. Size of L-sensor is $6{\times}7{\times}1.2mm$. When L-sensor was implanted in the eyes, it caused the inflammation. Therefore, this study suggests an inductive and capacitive type IOP sensor (LCsensor). The sensitivity of the LC-sensor 27.3 kHz/mmHg under 60mmHg. It is much larger than 14 kHz/mmHg of the L-sensor. And the size of LC-sensor is 47% smaller than L-sensor. After 2 weeks from the implantation of LC-sensor into rabbit eyes, we measured the changes of resonant frequency of LC-sensor according to increased IOP by Balanced Salt Solution (BSS) injection. As a result, the sensitivity of LC-sensor in in vivo test is 25 kHz/mmHg. That is similar to the sensitivity of in vitro test.

• Journal of the Korean Magnetics Society
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• v.22 no.3
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• pp.97-102
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• 2012

In this paper, a non-contact power transferring has been performed. Power Transferring by using an electromagnetic inductive coupling is more suitable for high power transmission than by using a magnetic resonance method. Power transferring system has been designed with Loading Distribution Method to divide the electric and magnetic loading for designing the magnetic core and electric coil. To design optimum shapes of magnetic yoke, 3D finite element analysis has been performed. Experimental results show good agreement with numerical ones. So, it could be adopted in the electric power transferring system for a short-distance wireless electric power transferring machine.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.64 no.11
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• pp.1651-1657
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• 2015

In MHz operating wireless power transfer systems, skin- and proximity-effect losses in the transmitter and the receiver coils dominate the coil-to-coil efficiency of the system. A Litz-wire was regarded as a common solution for minimizing such Ohmic losses in high frequencies. In this paper, equivalent series resistances of 12 different cables including Litz-wire and copper tubing have been calculated and measured for a 6.78 MHz, 100W, 30 cm wireless power transfer system. It has been shown that the copper tubing has lower resistances compared to the Litz-wire in that frequency and a wireless power transfer system with the copper tubing was able to achieve much higher efficiency than a system using the Litz-wire. Calculations of the resistances and efficiencies were accomplished with analytical equations and those calculations were evaluated by experimental results.

• Journal of the Optical Society of Korea
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• v.2 no.2
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• pp.74-79
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• 1998

The use of a fiber Fabry-Perot interferometer (FFPI) as an optical current transducer is demonstrated. A conventional inductive pickup coil converts the time-varying current I(t) being measured to a voltage waveform V(t) applied across a piezeolectric strip to which the FFPI is bonded. The strip experiences a longitudinal expansion and contraction, resulting in an optical phase shift ${\phi}(t)$ in the fiber proportional to V(t). This phase shift is measured using a frequency-modulated semiconductor light source, photodiodes to monitor the reflected light from the FFPI and the laser power, and a digital signal processor. Calibration routines compute V(t) and I(t) from the measured phase shift at a l KHz rate. Response to 60 Hz ac over the design range 0-1300A rms is characterized Transient response of the FFPI transducer is also measured.

• Proceedings of the Korea Institute of Applied Superconductivity and Cryogenics Conference
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• 2002.02a
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• pp.326-329
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• 2002

The dc reactor type superconducting fault current limiter is composed of a power converter, magnetic core reactors and a do reactor that is a superconducting coil. When a fault occurs, the dc reactor maintains the stability of system by limiting its fault current. In this study, we focus on the design of the dc reactor using FEM(Finite Element Method). In order to design it, various elements should be considered such as magnetic field intensity, Lorentz's force, its inductance and so forth. Firstly, we forecast the values of those elements from the simulation of FEM and then measured with a copper wire magnet. Finally, verify the reliability of this FEM method by comparing with two results.

• Progress in Superconductivity and Cryogenics
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• v.5 no.1
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• pp.92-96
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• 2003

This paper deals with the characteristics of persistent current switch (rCS) system fer applied HTS magnet system. To apply the high-Tc superconductor in superconducting machine such as motror, generator, MAGLEV, MRI, and NMR, the study on high-Tc superconducting persistent current mode must be performed. In this experiment, the PCS system consists otd superconducting magnet, PCS and magnet power supply. The superconducting magnet was fabricated by connecting four double pancake coils (DPCs) in series. The PCS was inductive double pancake coil type and heated up by the SUS 303L tape heater. The optimal length of PCS was calculated and thermal quench state of PCS was simulated by using finite element method(FEM) and compared with experimental results. The optimal energy to normalize the PCS was calculated and introduced. Finally, the persistent current was observed with respect to various ramping up rate and magnitude of charging current.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.53 no.3
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• pp.133-136
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• 2004

Low-Pressure inductively coupled RF discharge sources have important industrial applications mainly because they can provide a high-density electrodeless plasma source with low ion energy and low power loss. In an inductive discharge, the RF power is coupled to the plasma by an electromagnetic interaction with the current flowing in a coil. In this paper, the experiments have been focussed on the electric characteristic and carried out using a single Langmuir probe. The internal electric characteristics of inductively coupled Ar RF discharge at 13.56(MHz) have been measured over a wide range of power at gas pressure ranging from 1∼70(mTorr).

• The Transactions of The Korean Institute of Electrical Engineers
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• v.57 no.5
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• pp.816-820
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• 2008

The RF inductive discharge of inductively couples plasma (ICP) continues to attract growing attention as an effective plasma source in many industrial applications, the best known of which are plasma processing and lighting technology. Although most practical ICPs operate at 13.56 [MHz] and 2.65 [MHz], the trend to reduce the operating frequency is clearly recognizable from recent ICP developments. In an electrodeless fluorescent lamp, the use of a lower operating frequency simplifies and reduces cost of RF matching systems and RF generators and can eliminate capacitive coupling between the inductor coil and plasma, which could be a strong factor in wall erosion and plasma contamination. In this study, We discussed simulation and experimental results when changing ferrite position in antenna.

• Journal of Biomedical Engineering Research
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• v.7 no.1
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• pp.21-34
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• 1986

In this paper, we described the ECG telemetry system via the Public Telephone Line. The system consist of a signal acquisition and measurement section, a signal processing section, and a signal transmission section. It used 8 bits microprocessor. The transmission section is composed of 3 ch. analog modulators and 1 ct. digital modem. Especially, using the digital modem, signal is transmitted with about 50n data reduction ratio by the TP (Turning Point) algorithm. The acoustic coupler or inductive coil for linking the public telephone line are used. The speed of the digital modem is 300 baud rate. The MCBS (Multi Channel Biotelemetry System) is tested and evaluated through the experiment.