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Formulation of the Sucrose-Free Simulant Human Tissue for SAR Measurement at CDMA Mobile Band
Yoon-Myoung Gimm 한국전자파학회JEES 2007 Journal of Electromagnetic Engineering and Science Vol.7 No.2
A general method to formulate the tissue-equivalent liquids for SAR measurement is proposed to make sucrose-free brain tissue applicable at 835 MHz as an example. We suggest the tissue composition can be determined by measuring the dielectric constants and conductivities with the DI water and salt addition variation to the pre-manufactured auxiliary liquid of DGBE and TritonX-100. The manufactured liquid satisfies the specified electrical parameters of international standard at 835 ㎒.
Yoon-Myoung Gimm,Young-Jun Ju,Yu-Ri Lee,Dong-Yeol Lee,Jong-Wook Wang 한국전자파학회JEES 2011 Journal of Electromagnetic Engineering and Science Vol.11 No.4
A capsular endoscope (CE) for inspection of the large intestine requires a motor for backward navigation against the autonomous travel in the intestine. This study proposes an HF power system for generating a magnetic field and for delivering wireless power to the internal or implanted medical devices. The magnetic field is generated by a wound coil (L) around a wooden frame, and the current is driven to the coil through a resonating capacitor (C). The characteristics of the resonance frequency shifting of the L-C series circuit are analyzed. A stable magnetic field intensity in the field coil is maintained by a specially designed frequency tracking system that automatically follows the L-C resonance frequency. Testing confirmed that the oscillation system tracks well the parameter changes of the electric components caused by the operating conditions or environmental variations.
Yoon-Myoung Gimm,Jun Hee Kim 한국전자파학회JEES 2014 Journal of Electromagnetic Engineering and Science Vol.14 No.4
Dosimetry of radiating electromagnetic wave from mobile devices to human body has been evaluated by measuring Specific Absorption Rate (SAR). Usual SAR measurement system scans the volume by robot arm to evaluate RF power absorption to human body from wireless devices. It is possible to fast estimate the volume SAR by software deleting robot moving time with the 2D surface SAR data acquired by arrayed probes. This paper shows the principle of fast SAR measurement and the measured data comparison between the fast SAR system and the robot scanning system. Data of the fast SAR is well corresponding with data of robot scanning SAR within ±3 dB, and its dynamic range covers from 10 mW/kg to 30 W/kg with 4.8 mm probe diameter.
김윤명(Gimm Yoon-Myoung),주영준(Ju Young-Jun) 한국철도학회 2009 한국철도학회 세미나자료 Vol.2009 No.5
High speed train system generates much EMI (electromagnetic interference) by arc between the pantograph and the trolley line during the running time. EMI from the tilted EMU train system which is similar to HEMU-400X system for 400 km/h speed and with the distributed engines was measured following EN50121-2, 'Railway applications. - Electromagnetic compatibility (Emission of the whole railway system to the outside world)'. Measured EMI values exceed the limiting values of EN50121-2 in high frequency band (30 ㎒ - 1,000 ㎒), but exceeding frequencies were identified that they are used for mobile communications. Measured EMI values did not exceed the limiting values in other low frequency band between 9 ㎑ and 30 ㎒.
김윤명(Gimm Yoon-Myoung),주영준(Ju Young-Jun),유재성(Yoo Jea-Seong),구본철(Koo Bon-Chul) 한국철도학회 2008 한국철도학회 학술발표대회논문집 Vol.- No.-
High speed train system consumes much electric power during running, and generate much EMI (electromagnetic interference) by arc between the pantograph and the trolley line. In this paper, EMI was measured following EN50121-2, ‘Railway applications. ? Electromagnetic compatibility. (Emission of the whole railway system to the outside world)’, from the running high-speed railway (KTX) at 300 km/h speed. Measured results exceed the limit values of EN50121-2 in low frequency band (9 ㎑ ~ 150 ㎑), but they did not exceed the limit values in other higher frequency band (150 ㎑ ~ 1 ㎓).
동력 분산형 고속전철의 전자파 Source 및 Victim에 관한 연구
김윤명(Gimm Yoon-Myoung),주영준(Ju Young-Jun),구은희(Koo Eun-Hee),구본철(Koo Bon-Chul),유재성(Yoo Jae-Seong) 한국철도학회 2008 한국철도학회 학술발표대회논문집 Vol.- No.-
The high-speed EMU is assembled with distributed EMI sources. Therefore, it contains more electromagnetic sources nearby the distributed victims than the existing concentrated traction system. The electromagnetic sources and victims are identified in this research, and the methodology how to handle EMI/EMS/EMC of the high-speed EMU will be developed for safer operation. It includes measurement method, safety standards of control units and others, and performance evaluations of the firstly developed trial products for the EMU. Also influences by modern telecommunication equipments and effect of PLD(power line disturbance) are to be surveyed in this research.
무선통신서비스 주파수대역에서의 고속전철 시스템의 RFI 내성기준 및 측정방법 연구
김윤명(Gimm Yoon-Myoung),주영준(Ju Young-Jun) 한국철도학회 2008 한국철도학회 학술발표대회논문집 Vol.- No.-
Wireless telecommunication frequency band becomes wider with the development of modern telecommunication technology, and highly integrated semiconductors are applied more at high speed tain system. RFI susceptibilities of the integrated power semiconductors in high speed train system influence much on the system safety. RFI susceptibility standards and measurement methods in high speed train system at wireless telecommunication frequency band is surveyed in this research.
Effects of 60 Hz 14 µT magnetic field on the apoptosis of testicular germ cell in mice
Kim, Yoon‐,Won,Kim, Hee‐,Sung,Lee, Jin‐,Sang,Kim, Young‐,Jin,Lee, Sang‐,Kon,Seo, Jae‐,Nam,Jung, Kyeong‐,Cheon,Kim, Nam,Gimm, Youn‐,Myoung Wiley Subscription Services, Inc., A Wiley Company 2009 BioElectroMagnetics Vol.30 No.1
<P><B>Abstract</B></P><P>We recently reported that continuous exposure, for 8 weeks, of extremely low frequency (ELF) magnetic field (MF) of 0.1 or 0.5 mT might induce testicular germ cell apoptosis in BALB/c mice. In that report, the ELF MF exposure did not significantly affect the body weight or testicular weight, but significantly increased the incidence of testicular germ cell death. In the present study, we aimed to further characterize the effect of a 16‐week continuous exposure to ELF MF of 14 or 200 µT on testicular germ cell apoptosis in mice. There were no significant effects of MF on body weight and testosterone levels in mice. In TUNEL staining (In situ terminal deoxynucleotidyl transferase‐mediated deoxy‐UTP nick end labeling), germ cells showed a significantly higher apoptotic rate in exposed mice than in sham controls (<I>P</I> < 0.001). TUNEL‐positive cells were mainly spermatogonia. In an electron microscopic study, degenerating spermatogonia showed condensation of nuclear chromatin similar to apoptosis. These results indicate that apoptosis may be induced in spermatogenic cells in mice by continuous exposure to 60 Hz MF of 14 µT. Bioelectromagnetics 30:66–72, 2009. © 2008 Wiley‐Liss, Inc.</P>
Sangmu Lee,Yoon-Myoung Gimm,Changsoo Eun 한국전자파학회JEES 2010 Journal of Electromagnetic Engineering and Science Vol.10 No.4
In this paper, an electromagnetic induction on a telecommunication line by the distribution line of a power provision system or a feeder line of an electrified railway system has been verified through experiments. The basic cause of induction occurrence by these practical power provision systems is the returning current through the earth. This principle has been confirmed by the experiments documented in this paper which implemented these mechanisms to incur an induction. Experimental methods were used to produce the returning current through the earth. The experiment to find a relationship between inducing strength and the distance between the two phase lines in a power provision line has also been included to confirm that, when the distance is enlarged, the induction effect increases as the crossnullification effect of magnetic fluxes decreases. An experiment for the existence of a shielding effect by another conduction length material has been addedas a protection measure against the induction.
Automatic RF Input Power Level Control Methodology for SAR Measurement Validation
Ki-Hwea Kim,Dong-Geun Choi,Yoon-Myoung Gimm 한국전자파학회JEES 2015 Journal of Electromagnetic Engineering and Science Vol.15 No.3
Evaluation of radiating radiofrequency fields from hand-held and body-mounted wireless communication devices to human bodies are conducted by measuring the specific absorption rate (SAR). The uncertainty of system validation and probe calibration in SAR measurement depend on the variation of RF power used for the validation and calibration. RF input power for system validation or probe calibration is controlled manually during the test process of the existing systems in the laboratories. Consequently, a long time is required to reach the stable power needed for testing that will cause less uncertainty. The standard uncertainty due to this power drift is typically 2.89 %, which can be obtained by applying IEC 62209 in a normal operating condition. The principle of the Automatic Input Power Level Control System (AIPLC), which controls the equipment by a program that maintains a stable input power level, is suggested in this paper. The power drift is reduced to less than ±1.16 dB by AIPLC, which reduces the standard uncertainty of power drift to 0.67%.