• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2000년도 춘계학술대회 논문집 유기절연재료 방전 플라즈마
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• pp.74-77
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• 2000

The main objective of this paper is to design and test a new type of polymer ZnO surge arrester for AC power system of railroad vehicles. Metal oxide surge arrester for most electric power system applications, electric train and must not have explosive breakage of the housing to minimize damage to other equipment when subjected to internal high short circuit current. When breakdown of ZnO elements in a surge arrester occurs due to flashover, fault short current flows through the arrester and internal pressure of the arrester rises. The pressure rise can usually be limited by fitting a pressure relief diaphragm and transferring the arc from the inside to the outside of the housing. However, there is possibility of porcelain fragmentation caused by the thermal shock. pressure rise, etc. Non-fragmenting of the housing is the most desired way to prevent damage to other equipment. The pressure change which is occurred by flashover become discharge energy. This discharge energy raises to damage arrester housing and arrester housing is dispersed as small fragment. Therefore, the pressure relief design is requested to obstruct housing dispersion. The main research works are focused on the structure design by finite element method, pressure relief of module, and studies of performance of surge arrester for electric railway vehicle.

• 센서학회지
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• 제6권4호
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• pp.307-315
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• 1997

본 논문에서는 센서교환이 용이하고 소량의 샘플을 요구하는 ISFET 센서용 전해질 분석기의 샘플챔버(sample chamber)를 설계하였으며, 이를 이용한 2점 교정방식의 4채널 전해질 분석기를 구현하였다. 샘플과 교정용액들의 사용을 최소화하기 위한 샘플의 로딩상태 감지회로를 제안하였으며 이를 실현하였다. 구현된 전해질 분석기는 제어계통과 액류흐름계통으로 구성되어 있으며 전해질 분석기의 효과적인 제어를 위하여 측정루틴, 교정루틴 및 세척루틴의 시스템 소프트웨어를 각각 개발하였다.

• 감성과학
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• 제20권4호
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• pp.113-126
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• 2017

The purpose of the study was to find grey matter (GM) and white matter (WM) volume reduction in the brain reward system among patients with alcohol dependency. This study investigated regional GM and WM in chronic alcoholic patients, focusing primarily on the reward system, including principal components of the mesocorticolimbic reward circuit as well as cortical areas with modulating and oversight functions. Sixteen abstinent long-term chronic alcoholic men and demographically matched 16 healthy control men participated in the study. Morphometric analysis was performed on magnetic resonance brain scans using voxel-based morphometry (VBM)-diffeomorphic Anatomical Registration through Exponentiated Liealgebra (DARTEL). We derived GM and WM volumes from total brain and cortical and subcortical reward-related structures. Morphometric analyses that revealed the total volume of GM and WM was reduced and cerebrospinal fluid (CSF) was increased in the alcohol group compared to control group. The pronounced volume reduction in the reward system was observed in the GM and WM of the nucleus accumbens (NAc), GM of the amygdala, GM and WM of the hippocampus, WM of the thalamus, GM and WM of the insula, GM of the dorsolateral prefrontal cortex (DLPFC), GM of the orbitofrontal cortex (OFC), GM of the cingulate cortex (CC), GM and WM of the parahippocampal gyrus in the alcohol group. We identified volume reductions in WM as well as GM of reward system in the patients with alcohol dependency. These structural deficits in the reward system elucidate underlying impairment in the emotional and cognitive processing in alcoholism.

• The Korean Journal of Physiology and Pharmacology
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• 제5권3호
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• pp.231-241
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• 2001

The mammalian cortical collecting duct (CCD) plays a major role in regulating renal NaCl reabsorption, which is important in $Na^+$ and $Cl^-$ homeostasis. The M-1 cell line, derived from the mouse cortical collecting duct, has been used as a mammalian model of the study on the electrolytes transport in CCD. M-1 cells were grown on collagen-coated permeable support and short circuit current $(I_{sc})$ was measured. M-1 cells developed amiloride-sensitive current $5{\sim}7$ days after seeding. Apical and basolateral addition of ATP induced increase in $I_{sc}$ in M-1 cells, which was partly retained in $Na^+-free$ or $Cl^--free$ solution, indicating that ATP increased $Na^+$ absorption and $Cl^-$ secretion in M-1 cells. $Cl^-$ secretion was mediated by the activation of apical cystic fibrosis transmembrane regulator (CFTR) chloride channels and $Ca^{2+}-activated$ chloride channels, but $Na^+$ absorption was not mediated by activation of epithelal sodium channel (ENaC). ATP increased cAMP content in M-1 cells. The RT-PCR analysis demonstrated that M-1 cells express $P2Y_2,\;P2X_3\;and\;P2Y_4$ receptors. These results showed that ATP regulates $Na^+$ and $Cl^-$ transports via multiple P2 purinoceptors on the apical and basolateral membranes in M-1 cells.

• 스마트미디어저널
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• 제2권1호
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• pp.27-30
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• 2013

논문에서는 EPIC(Electronic Potential Integrated Circuit) 센서를 이용한 Hand tracking 및 Calibration 알고리즘을 연구하였다. 주변의 전위차를 감지하는 EPIC 센서의 특성을 분석하고, 이러한 특성을 고려한 EPIC 센서들 간의 감지된 진폭의 차를 이용하여 이차원 좌표 변환을 구현하였다. 이에 추가적으로 주변 환경에 민감한 EPIC 센서의 특성을 고려한 Calibration 알고리즘을 구현하였으며, 효과적으로 목표물을 추적하도록 칼만 필터 알고리즘을 적용하였다. 구현된 알고리즘은 검증 및 분석을 위해 윈도우 어플리케이션 환경으로 구현하였으며 EPIC 센서의 아날로그 데이터를 추출하기 위해 DAQ(Data Acquisition) API 함수를 사용하였다, DAQ 하드웨어는 전기적 신호를 측정 및 생성할 수 있는 기능을 가지고 있으며, DAQ API를 통해 아날로그 또는 디지털 신호를 측정 및 생생할 수 있다. 측정된 아날로그 신호를 구현된 알고리즘을 통해 사용자의 손의 움직임에 따라 EPIC 센서에서 전위차를 감지함으로써 PC의 mouse cursor 움직임을 확인한다.

• 조명전기설비학회논문지
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• 제15권3호
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• pp.67-73
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• 2001

본 논문에서는 ZnO 피뢰기 소자에 대한 내구성 평가와 열화실험을 위한 저항분 누설전류 검출장치의 개발과 열화진단기법에 대하여 기술하였다. 저항분 누설전류는 ZnO 피뢰기 소자가 정상상태인지 불안정상태인지에 대한 판단의 지표로서 사용할 수 있다. 본 논문에서는 보상회로로 구성된 저항분 누설전류 측정시스템을 설계하여 구성하고, 실증실험으로서 ZnO 소자에 대한 저항분 누설전류의 측정과 고속프리에 변환기법(Fast Fourier transform)을 통해 저항분 누설전류의 주파수특성을 조사·분석하였다. 분석결과 제안한 저항분 누설전류의 측정 시스템은 실험실에서 산화아연 바리스터의 전기적·물성적 특성을 연구하고, 전력계통에 있어서 ZnO 피뢰기의 열화의 진단과 예측기술을 개발하는데 유용하게 활용할 수 있다.

• 한국산학기술학회논문지
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• 제17권5호
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• pp.49-55
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• 2016

각종 전기전자 시스템에서 발생하는 EMI 성분을 공통성분 (CM) 과 차동성분 (DM) 으로 분리하기 위해서 수동분리기와 능동분리기를 연구하였다. CM과 DM 성분 분리기는 능동 EMI 필터를 효과적으로 구현하는데 중요한 요소이다. 수동분리기는 인덕터값을 실현하는데 있어 기술적으로 쉽고 가격이 저렴한 장점이 있으나 상대적으로 큰 오차값이 발생하여 정밀 제작이 요청되므로 부피가 커지고 core의 선택이 어려워지는 단점이 있다. 능동분리기는 OP-Amp를 이용하기 때문에 부피가 작아지고 CM, DM 분리의 정확도를 높일 수 있는 장점이 있으나 주파수 특성이 광대역이어야 하고 가격이 비싸며 별도 DC 전원이 요청되는 단점이 있다. 본 연구에서는 기존의 수동 분리기와 새롭게 제안한 능동 분리기를 적용한 각각의 EMI 필터의 특성을 분석하였다. 따라서 높은 정밀도가 필요한 고가의 장비에는 능동 분리기를 사용하는 것이 정밀도를 개선하는데 유리하며, 일반적인 용도로 저렴한 가격이 요청되며 충분한 설계 면적을 활용할 수 있고 높지 않은 정확도에서도 동작 가능하다면 수동 분리기가 더 바람직하다.

• Journal of Power Electronics
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• 제18권1호
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• pp.70-80
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• 2018

A novel strategy based on a zero common mode voltage pulse-width modulation (ZCMV-PWM) technique and zero-sequence circulating current (ZSCC) feedback control is proposed in this study to eliminate ZSCCs between three-level neutral point clamped (NPC) voltage source inverters, with common AC and DC buses, that are operating in parallel. First, an equivalent model of ZSCC in a three-phase three-level NPC inverter paralleled system is developed. Second, on the basis of the analysis of the excitation source of ZSCCs, i.e., the difference in common mode voltages (CMVs) between paralleled inverters, the ZCMV-PWM method is presented to reduce CMVs, and a simple electric circuit is adopted to control ZSCCs and neutral point potential. Finally, simulation and experiment are conducted to illustrate effectiveness of the proposed strategy. Results show that ZSCCs between paralleled inverters can be eliminated effectively under steady and dynamic states. Moreover, the proposed strategy exhibits the advantage of not requiring carrier synchronization. It can be utilized in inverters with different types of filter.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2007년도 하계학술대회 논문집 Vol.8
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• pp.45-45
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• 2007

Capacitors among the embedded passive components are most widely studied because they are the major components in terms of size and number and hard to embed compared with resistors and inductors due to the more complicated structure. To fabricate a capacitor-embedded PCB for in-line process, it is essential to adopt a low temperature process (<$200^{\circ}C$). However, high dielectric materials such as ferroelectrics show a low permittivity and a high dielectric loss when they are processed at low temperatures. To solve these contradicting problems, we studied BMN materials as a candidate for dielectric capacitors. processed at PCB-compatible temperatures. The morphologies of BMN thin films were investigated by AFM and SEM equipment. The electric properties (C-F, I-V) of Pt/BMN/Cu/polymer were evaluated using an impedance analysis (HP 4194A) and semiconductor parameter analyzer (HP4156A). $Bi_2Mg_{2/3}Nb_{4/3}O_7$(BMN) thin films deposited on copper clad laminate substrates by sputtering system as a function of Ar/$O_2$ flow rate at room temperature showed smooth surface morphologies having root mean square roughness of approximately 5.0 nm. 200-nm-thick films deposited at RT exhibit a dielectric constant of 40, a capacitance density of approximately $150\;nF/cm^2$, and breakdown voltage above 6 V. The crystallinity of the BMN thin films was studied by TEM and XRD. BMN thin film capacitors are expected to be promising candidates as embedded capacitors for printed circuit board (PCB).

• 한국전기전자재료학회논문지
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• 제23권7호
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• pp.571-574
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• 2010

Surface recombination loss should be reduced for high efficiency of solar cells. To reduce this loss, the BSF (back surface field) is used. The BSF on the back of the p-type wafer forms a p+layer, which prevents the activity of electrons of the p-area for the rear recombination. As a result, the leakage current is reduced and the rear-contact has a good Ohmic contact. Therefore, the open-circuit-voltage (Voc) and fill factor (FF) of solar cells are increased. This paper investigates the formation of the rear contact process by comparing aluminum-paste (Al-paste) with pure aluminum-metal(99.9%). Under the vacuum evaporation process, pure aluminum-metal(99.9%) provides high conductivity and low contact resistance of $4.2\;m{\Omega}cm$, but It is difficult to apply the standard industrial process to it because high vacuum is needed, and it's more expensive than the commercial equipment. On the other hand, using the Al-paste process by screen printing is simple for the formation of metal contact, and it is possible to produce the standard industrial process. However, Al-paste used in screen printing is lower than the conductivity of pure aluminum-metal(99.9) because of its mass glass frit. In this study, contact resistances were measured by a 4-point probe. The contact resistance of pure aluminum-metal was $4.2\;m{\Omega}cm$ and that of Al-paste was $35.69\;m{\Omega}cm$. Then the rear contact was analyzed by scanning electron microscope (SEM).