Journal of Yeungnam Medical Science

Joon Ha Lee

7 Articles

A Transcutaneous Energy and Data Transmission for Implantable FES Devices: Joon Ha Lee; Yeungnam Univ J Med. 2007;24(2 Suppl):S472-480. Published online December 31, 2007; DOI: https://doi.org/10.12701/yujm.2007.24.2S.S472

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Abstract PDF: Background
：Inductive coupling links are frequently used for powering of implanted devices for functional electrical stimulation (FES) and cochlear. They are used in applications where implanted batteries are not capable of supplying a sufficient amount of power over the time of implantation or where continuous data exchange with external components is necessary like in a leg pacemaker. Materials and Methods：This paper describes an inductive power transmission link, which was developed for an implantable stimulator for direct stimulation of denervated muscles. The carrier frequency is around 1 MHz, the transmitter coil has a diameter of 46 mm, and the implant coil is 46 mm. Data transmission to the implant with amplitude shift keying (ASK) and back to the transmitter with passive telemetry can be added without major design changes.
Results
：We chose the range of coil spacing (2 to 30 mm) to care for lateral misalignment, as it occurs in practical use. If the transmitter coil has a well defined and reliable position in respect to the implant, a smaller working range might be sufficient. Under these conditions the link can be operated in fixed frequency mode, and reaches even higher efficiencies of up to 37%. The link transmits a current of 50 mA over a distance range of 2-15 mm with an efficiency of more than 20% in tracking frequency.
Conclusion
：The efficiency of the link was optimized with different approaches. A class E transmitter was used to minimize losses of the power stage. The geometry and material of the transmitter coil was optimized for maximum coupling. Phase lock techniques were used to achieve frequency tracking, keeping the transmitter optimally tuned at different coupling conditions caused by coil distance variations.

Implantable Functional Electrical Stimulation with Inductive Power and Data Transmission System.: Joon Ha Lee; Yeungnam Univ J Med. 2007;24(2):97-106. Published online December 31, 2007; DOI: https://doi.org/10.12701/yujm.2007.24.2.97

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Abstract PDF: Functional electrical stimulation (FES) has developed over the last 35 years to become a scientifically, technologically and clinically recognized field of interest in clinical medicine. FES has been applied to locomotion, grasping, ventilation, incontinence, and decubitus healing. However, all of these achievements illustrate the initial applications of FES; its true potential has not yet been realized. Recently, FES systems, which are miniaturized stimulation devices, have been utilized in the clinical setting. However, because the stimulating electrodes of the current FES devices are percutaneous electrodes, which are susceptible to wire breakage, and skin infection an implantable FES stimulating electrode has been introduced in the U.S. and Japan. In the present study, an external power supply method using radio frequency (RF) coupling and data transmission was developed for the control of the implantable FES device. In addition, we review the current understanding of FES devices and their application in clinical medicine.

The Effects of Microwave Irradiated on Rabbit's ICP.: Jin Han Park, Seong Ho Kim, Dong Ro Han, Jang Ho Bae, Oh Lyong Kim, Byung Yon Choi, Soo Ho Cho, Joon Ha Lee; Yeungnam Univ J Med. 1994;11(2):213-220. Published online December 31, 1994; DOI: https://doi.org/10.12701/yujm.1994.11.2.213

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Abstract PDF: Damages on central nervous system induced by the exposure of microwave. However, the effects of microwave on ICP are not studied yet. The ICP affected by the condition of the condition of the brain has an significant effect on vital sign. So we investigated the changes of ICP of the rabbits after exposure. Twenty four rabbits were divided into 3 groups depending on the amount of exposure to microwave. One group was composed with 8 rabbits were exposed to microwave for 10 miniutes. Other were composed to microwave for 20 miniutes, 30 miniures, respectively. Intracranial pressure on each group were measured by subdural type ICP monitoring catheter immediately, first day, 3rd day, 5th day and 7th day after exposure of microwave. Results indicates that intracranial pressure of rabbits are not affected with statistical significance by exposure of microwave.

Fundamental Study for Rolling-Over Motion of the Body by Functional Electrical Stimulation (FES).: Joon Ha Lee, N Hoshimiya; Yeungnam Univ J Med. 1990;7(2):103-108. Published online December 31, 1990; DOI: https://doi.org/10.12701/yujm.1990.7.2.103

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Abstract PDF: A method to roll-over the paralyzed body by means of Functional Electrical Stimulation (FES) is considered. It is demonstrated that individual joint motions necessary for the rolling-over are realized by electrical stimulation. EMG measurements are also performed to analyze the cooperative activities of the muscles during rolling-over motion in a case where an upper extremity was used. These results of two experiments using normal subjects verifies the fundamental feasibility of body control by FES.

A Design of High-Frequency Oscillatory Ventilator Using Phase Lock Loop system.: Sang Hag Lee, Dong Gyo Jeong, Joon Ha Lee, Kwan Ho Lee, Young Jo Kim, Jae Chun Chung, Hyun Woo Lee, Suck Kang Lee, Tae Sug Lee; Yeungnam Univ J Med. 1989;6(2):217-222. Published online December 31, 1989; DOI: https://doi.org/10.12701/yujm.1989.6.2.217

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Abstract PDF: In this study, high frequency oscillatory ventilator was designed and constructed. Using designed by phase-lock loop system, in order to accurately and easily treat both the outlet volume and rpm. A system has been designed and is being evaluated using CD4046A PLL IC. We use this PLL IC for the purpose of motor controls. The device consists of PLL system, pumping mechanism, piston, cylinder, and special crank shaft are required. This system characteristics were as follows: 1) Frequency: 20-1800 rpm 2) Outlet air volume: 1-50 cc

A Study on the Design of High-Frequency Jet Ventilator Using PLL system.: Joon Ha Lee, Jae Chun Chung; Yeungnam Univ J Med. 1989;6(2):63-70. Published online December 31, 1989; DOI: https://doi.org/10.12701/yujm.1989.6.2.63

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Abstract PDF: This paper describes to design and to examine the mechanical characteristics of high frequency jet ventilator. The device consists of Phase lock loop (PLL) system, solenoid valve driving control part and Air regulating system. This study is carried out by changing several factors such as endotracheal tube (E.T. tube) diameter, injector cannula diameter, 1%, and frequency (breaths/min.) having direct effects on the gas exchange as well as parameters of the entrained gas by venturi effect, so as to measure the tidal volume and minute volume. This system characteristics were as follows: 1) Frequency: 6-594 bpm 2) Inspiration time: 1-99% 3) Variance of input air pressure: 1-30 PSI

A Study on the Development of R-R Interval Analyzer using Microcomputer (1).: Joon Ha Lee, Soo Bong Choi; Yeungnam Univ J Med. 1985;2(1):77-80. Published online December 31, 1985; DOI: https://doi.org/10.12701/yujm.1985.2.1.77

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Abstract PDF: The R-R interval analyzer was developed to measure the autonomic nervous system function using microcomputer. The system based on 8 bit microcomputer including bandpass filter, R-wave detector and clock generator in order to obtain the mean value, standard deviation, total time, CV value, maximum value and minimum value in the specific view point of R-R interval variation. The pattern of R-R interval change after resting, voluntary standing and deep breathing can be analyzed in normal subjects and diabetics with autonomic nervous dysfunction. The amplitude of the R-R interval variation showed sensitive pattern for normal subjects at resting, standing and deep breathing. On the contrary, the periodicities of amplitude for abnormal subjects with autonomic nervous dysfunction showed dull pattern. It was suggested that R-R interval analyzer is a good detection method for dysfunction of autonomic nervous system.

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