• 한국멀티미디어학회논문지
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• 제21권1호
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• pp.34-44
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• 2018

An early detection of intravenous (IV) infiltration is essential to minimize the injuries during infusion therapy, which is one of the most important tasks for nurses in nursing settings. We report that bioelectrical impedance analysis is useful in the early detection of infiltration at puncture sites. When infiltration was intentionally induced in the vein of a pig's posterior ear, impedance parameters (R, $X_C$, $C_m$) showed significant differences before and after infiltration. In particular, the relative resistance ($R/R_{BI}$) decreased significantly at infiltration and then slowly decreased. This indicates that the vein in pig's ear is thin and the amount of surrounding subcutaneous tissue, and hence the infiltrated solution accumulates slowly after infiltration. However, when infiltration was induced in the vein of human's forearm, the relative resistance at 20 kHz decreased gradually over time. In the $R-X_C$ graph, the positions in the case of infiltration induced in the pig' ear shifted rapidly before and after infiltration, whereas the positions in the case of infiltration induced in the human's forearm moved gradually during infiltration. Our findings suggest that the impedance parameters (R, $R/R_{BI}$, $X_C$, R vs. $X_C$, and $C_m$) are effective indicators to detect the infiltration early in a non-invasive and quantitative manners.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2006년도 하계학술대회 논문집 Vol.7
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• pp.438-439
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• 2006

We have used ITO/$Alq_3$/Al structure to study complex impedance in $Alq_3$ based organic light emitting diode. Equivalent circuit was analyzed in a device structure of ITO/$Alq_3$/Al by varying the thickness of $Alq_3$ layer from 60 to 400nm. The impedance results can be fitted using equivalent circuit model of parallel combination resistance $R_p$ and capacitance $C_p$ with a small series resistance $R_s$.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1995년도 하계학술대회 논문집 A
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• pp.30-32
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• 1995

The model interrupters of $SF_6$ gas electromagnetic contactor whose ratings are the voltage of 7.2kV and the short circuit current of 4.0kA have been designed and manufactured on the basis of theoretical and computational analysis for its development. The eddy current analysis, the magnetic field analysis and the calculation of the rotational force on arcs have been conducted using FLUX2D package. The short circuit current interrupting tests have been conducted to the model interrupters using the simplified capacitive synthetic test circuit in KERI. The results show that the model interrupters have a sufficient interrupting capability and the new design concept is proper for a good interrupting performance.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1995년도 하계학술대회 논문집 A
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• pp.160-164
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• 1995

In order to develop a medium voltage class gas circuit breaker by our own technology, we designed and manufactured the model interrupters using the hybrid arc extinguishing principle which adopts the thermal expansion principle in the large current region and the arc rotation principle by permanent magnet in the small current region. As the results of the first year research out of three years' research period, the main design parameters such as the volume of thermal expansion chamber, the distance between fixed contact and nozzle, the length of nozzle throat, the nozzle expansion angle and the magnitude of permanent magnet etc. have been determined. 4 types of model interrupters have been designed and manufactured considering the main design parameters. The 25kA short-circuit test and capacitive current breaking test have been performed for the model interrupters and the test results analyzed to improve the model interupters.

• 한국표면공학회지
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• 제31권5호
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• pp.245-250
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• 1998

There is clear pressing need to reduce bias field(Ha,) used on linear magenetomechanical resonator tag by at least a factor of two to allow low-bias operation near the frequency minimum since reducing Ha causes a dramatic increase in well depth, which implies increased stability. However, this makes it more difficult to maintain tight frequncy specs. It can be solved by a reduction of magnetomechanical coupling(k). We determined from an equivalent circuit model that optimal reduced, k, is near 0.3 Also, We determiend the material properties($lambda_s$, :saturated magenetostriction, $M_s$, and,$H_a$) that give k=0.3. From these evaluations, we suggested that on optimal comosition with adequate mathrial properties is $Fe_{55}Co_{15}Cr_6Nb_2B_{18}Si_4$.

• 전력전자학회논문지
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• 제16권2호
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• pp.199-207
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• 2011

전기 장치용 리튬폴리머 전지의 전기적 모델링은 전기에너지 공급시스템의 특성을 파악하는데 매우 중요하다. 본 논문은 리튬폴리머 전지의 동적특성을 모사하기 위한 전기적 등가 모델을 제안하였다. 리튬폴리머 전지의 충/방전 실험은 Maccor 8500 충방전시험장치를 사용하였다. 측정된 데이터를 이용하여 전지의 R-C 값을 선정하였으며, 선정된 값은 다항식 함수와 지수 함수를 사용하여 수식으로 나타내었다. 시뮬레이션 결과와 실험결과를 비교하여 제안된 모델의 타당성을 검증하였다

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2005년도 추계학술대회 논문집 Vol.18
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• pp.277-278
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• 2005

Admittance Spectroscopic analysis was applied to study the effect of LiF buffer layer and to model the equivalent circuit for poly(2-methoxy-5-(2'-ethylhexyloxy)-1,4-phenylenevinylene) (MEH-PPV)-based polymer light emitting diodes (PLEDs) with the LiF cathode buffer layer. The single layer device with ITO/MEH-PPV/Al structure can be modeled as a simple parallel combination of resistor and capacitor. Insertion of a LiF layer at the Al/MEH-PPV interface shifts the highest occupied molecular orbital level and the vacuum level of the MEH-PPV layer as a result the barrier height for electron injection at the Al/MEH-PPV interface is reduced. The admittance spectroscopy measurement of the devices with the LiF cathode buffer layer shows reduction in contact resistance ($R_c$), parallel resistance ($R_p$) and increment in parallel capacitance ($C_p$).

• 전자공학회논문지SC
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• 제40권5호
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• pp.350-354
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• 2003

본 논문에서는 능동 클램프 스위치를 위한 별도의 구동 회로가 생략된 새로운 자기 구동 능동 클램프 포워드 컨버터를 제안하였다. 능동 클램프 스위치의 구동에는 컨버터 자체의 변압기의 보조 권선을 이용하였고, 두 스위치 구동 신호 사이의 데드 타임을 설정하기 위하여 간단한 R-C지연 회로를 추가하였다. 제안된 컨버터의 동작 원리를 제시하였고 실험 결과를 가지고 이론적인 결과를 입증하였다. 출력 100W(5V/20A)의 컨버터를 제작하였으며 입력이 50V일 때 능동 클램프 스위치의 구동에 단지 1.5T의 보조 권선의 권선수로 충분하다는 점을 보였다. 끝으로 제안된 컨버터의 측정 효율을 제시하였고 91%의 최대 효율을 달성하였다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2007년도 하계학술대회 논문집 Vol.8
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• pp.232-233
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• 2007

We manufactured Liquid Crystal Polymer (LCP) and (1-x)CaTiO3-xLaAlO3 (CT-LA) ceramic composites and investigated dielectric properties to use as embedded capacitor in printed circuit boards and replace LTCC substrate. The dielectric properties of these composites are varied with volume fraction of CT-LA and ratios of CT/LA. Dielectric constants are in the range of 3~15. In addition, we could get low TCC and High Q value that could not achieve in other ceramic-polymer composites. Especially, in composite with x=0.01 and 30 vol% CT-LA, the dieletric constant and Q-value are 10 and 200, respectively. And more TCC is $-28{\sim}300ppm/^{\circ}C$ in the temperature range of $-55{\sim}125^{\circ}C$. We think that this composites can be used high-Q substrate material like LTCC and embedded temperature compensation capacitor in printed circuit boards.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1990년도 하계학술대회 논문집
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• pp.215-220
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• 1990

A.C. impedance properties of $RuO_2$ based thick film resistors which having different resistivity value (DuPont 1721 : $100{\Omega}$/ sq., 1741 : $10K{\Omega}$/sq.) were investigated using by impedance analyzer. In case of lower resistivity 1721 system, the complex impedance was composed nearly R component for all speciman sintered at above $600^{\circ}C$, and the frequency dependancy on impedance was not affected very much up to 5MHz and again gradually increase with increasing the frequency. In case of higher resistivity 1741 resistor system, impedance properties were very depandant on sintering temperature. When sintering temperature was $600^{\circ}C$, the complex impedance plot shows a vertical line, which correspond to lone capacitance equivalant circuit, and the impedance linearly decreased with increasing frequency. In case of speciman sintered at $700-900^{\circ}C$, the complex impedance plot shows semi-circular are correspond to a lumped RC combination, and the impedance shows constant value to 5MHz, again decreased with increasing frequency. But the complex impedance behavior of speciman sintered at $1000^{\circ}C$ was shows the equivalent circuit correspont to parallel combined LCR component, and the impedance was not varied with frequency.