• 한국조명전기설비학회지:조명전기설비
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• 제9권4호
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• pp.93-102
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• 1995

The purpose of this paper is to analyze the streaming electrification mechanism (SEM) generated in UHV transformer. This experiment used Couette Charger and interpreted the mechanism hydromechanically and electromagnetically. This work estimated the turbulent core density ($\rho$o) by measuring the short circuit current (isc) and the open circuit voltage (νoc) generated in Couette Charger and also studied the changes of the short circuit (isc), the open circuit voltage (νoc), the turbulent core density ($\rho$o) and the conductivity ($\sigma$) with adding BTA to restrain streaming electrification. as a result adding BTA increased the conductivity of oil and decreased the turbulent core density($\rho$o).

• The Korean Journal of Physiology and Pharmacology
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• 제8권5호
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• pp.289-293
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• 2004

To investigate whether VacA (vacuolating toxin) produced by Helicobacter pylori Korean stain 99 induces intestinal secretion, purified VacA was added to T84 cell monolayers mounted in Ussing chambers, and electrical parameters were monitored. Mucosal addition of low pH-pretreated VacA increased short circuit current (Isc). The effect was time- and dose-dependent and saturable. The time-to-peak Isc was concentration-dependent. Chloride channel inhibitors, niflumic acid or 5-nitro-2-(3-phenylpropylamino)-benzoate (NPPB), inhibited VacA-stimulated Isc. Carbachol (CCh)-induced increase of Isc was prolonged by the addition of VacA to the mucosal side only. The effect was unaltered by the addition of niflumic acid. VacA did not show cytopathic effects. These studies indicate that VacA is a nonlethal toxin that acts in a polar manner on T84 monolayers to potentiate $Cl^-$ secretion and the response to CCh secretion without decrease in monolayer resistance. VacA may contribute to diarrhea diseases in human intestinal epithelial cells.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2008년도 하계학술대회 논문집 Vol.9
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• pp.3-4
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• 2008

Photovoltaic module consists of serially connected solar cell which has low voltage characteristics. But, the other way, the whole current flow of PV module is restricted by lowest current of one solar cell. For the experiment, we make PV module composing the solar cells that have short circuit current difference of 0%, 1%, 3% and 5%. Using Light I-V and Dark I-V measurements, electrical characteristic parameters like Isc(short-circuit current), Voc(open-circuit voltage), Rs(series resistance), Rsh(shunt resistance) are analyzed. PV module of low current characteristics has electrical stress from other modules. And, such a module has a tendency of hot-spot suffering which leads degradation.

• 한국태양에너지학회:학술대회논문집
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• 한국태양에너지학회 2008년도 추계학술발표대회 논문집
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• pp.36-41
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• 2008

In this paper, we study The Effects of PV Cell's Electrical Characteristics for PV Module Application. Photovoltaic module consists of serially connected solar cell which has low open circuit voltage and high short circuit current characteristics. The whole current flow of PV module is restricted by lowest current of one solar cell. For the experiment, we make PV module composing the solar cells that have short circuit current difference of 0%, 1%, 3% and Random. The PV module exposed about 35days, its the maximum power drop ratio was 4.282% minimum and 6.657% maximum. And PV module of low current characteristics has electrical stress from other modules. The solar cell temperature of PV module was higher compared to PV cell. To prevent early degradation, it is need to have attention to PV cell selection.

• 전자공학회논문지SC
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• 제48권2호
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• pp.15-21
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• 2011

본 논문에서는 $0.35{\mu}m$ CMOS 공정을 이용하여 태양 에너지 하베스팅을 위한 에너지 관리 시스템을 설계하였다. 태양 에너지 관리 시스템은 ISC(Integrated Solar Cell), voltage booster, MPPT(Maximum Power Point Tracker) control unit으로 구성된다. ISC의 개방전압은 약 0.5V이고, 단락 전류는 약 $15{\mu}A$이다. Voltage booster는 뒷단에 약 1.5V로 승압된 전압을 공급한다. MPPT control unit은 ISC가 MPP점에 도달 하였을 때, load로 전력이 전달될 수 있도록 pMOS 스위치를 동작시킨다. SEMU(Solar Energy Management Unit)의 크기는 패드를 포함하여 $360{\mu}m{\times}490{\mu}m$이다. ISC의 면적은 $500{\mu}m{\times}2000{\mu}m$이다. 제작된 칩을 측정한 결과 설계된 SEMU가 ISC에서 수확된 에너지에 대해 MPPT control 동작을 제대로 수행하는 것을 확인하였다. 측정된 MPP 전압범위는 약 370mV∼420mV이다.

• Journal of Welding and Joining
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• 제17권5호
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• pp.61-68
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• 1999

For the last two decades, waveform control techniques have been successively developed and applied for the inverter welding machines resulting in the substantial reduction of spatter generated in CO₂ welding. One of the constituents commonly involved in those techniques is to delay the instant of current increase to some extent after the initiation of short-circuiting. Although this technique has been known to be quite effective in reducing the spatter generation through the suppression of is instantaneous short circuiting, the delay time necessary for minimum spatter has not been clearly understood. In this study, the control system for varying the delay time was constructed so that the spatter generation rates could be measured over a wide range of delay time, 0.29-2.0 msec. As a result of this study, it was demonstrated that spatter generation rate(SGR) sharply decreased at delay time of 0.6 msec and longer accompanied with the change in characteristics of short circuit mode from the instantaneous short-circuiting(ISC) dominant to normal short-circuiting(NSC) dominant. Another feature that have been found in current waveform of over 0.6msec was the creation of current pulse right after the arc reignition stage. Because of this current pulses weld pool oscillated in wave-like fashion and it looks like to play an important role in developing short circuiting between electrode and weld pool.

• 한국항공우주학회지
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• 제49권12호
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• pp.1019-1025
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• 2021

거의 모든 우주 환경에서 태양전지 열화는 양성자에 의해 좌우된다. 정지궤도는 전자 방사선 벨트에 위치하지만 태양 이벤트에서 방출된 양성자는 여전히 태양전지 열화의 주된 요소이다. 2010년 6월 26일 천리안 1호가 발사된 이후로, 2012년 1월 23일에서 29일 그리고 2012년 3월 7일에서 14일에 다년 평균 관측 수준의 약 30배 이상의 플루언스를 갖는 양성자 이벤트가 관측되었다. 본 논문은 2012년 1월과 3월에 발생한 태양 양성자 이벤트에 의해 감시 셀의 개방회로 전압(Voc)과 션트 스위치에 연결된 한 섹션의 단락회로 전류(Isc)에 대한 태양전지 열화에 대해 연구한다. 태양전지의 성능을 평가하기 위해 전압과 전류의 비행 데이터는 온도, 지구-태양 거리, 태양 각도로 보정한 후 임무 초기 태양전지 특성과 비교한다. Voc 전압은 2012년 1월 양성자 이벤트 이전과 비교하여 2012년 3월 양성자 이벤트 이후에 약 23.6mV 감소되었다. 감소된 Voc 전압은 임무 초기값 2575mV에 대해 1% 미만이다. Isc 전류는 예상대로 2012년 3월 양성자 이벤트에서 무시할 정도로 감소되었다.

• 한국태양에너지학회:학술대회논문집
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• 한국태양에너지학회 2008년도 춘계학술발표대회 논문집
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• pp.257-262
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• 2008

In this paper, we study the electric characteristics of shading effects in photovoltaic module in case of outdoor operation. When fabricating PV module, solar cells are connected serially to obtain the high voltage because of its low open circuit voltage. And total current is determined by lowest current among solar cells. When the shading happens on PV module's surface, the current of shaded solar cell determine the total current flow. Because of this, generally by-pass diode is installed on junction box. The bypass diode operate when revered and shaded solar cell's voltage is over 0.6 voltage. The reverse-biased solar cell gives reduced maximum power of PV module and might give negative effect on durability. So, adequate by-pass installation and selection is needed.

• 신재생에너지
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• 제5권3호
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• pp.22-25
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• 2009

For increasing the output voltage, six SMD(surface mount device) type AlGaAs/GaAs solar cells were connected in series. The electrical properties of the array were measured and compared with one sun (100 mW/$cm^2$) and indoor light (480 lux) conditions. Under one sun condition, output power was 21.57 mW and it was $14.67\;{\mu}W$ under indoor light condition. Under the indoor light condition, the intensity of the light is very low compared to one sun condition. Thus the Voc(open circuit voltage) and Isc (short circuit current) of the sample under indoor light condition decreased very much compared to that of under the one sun condition. This kind of solar cell power supply can be used as a power source for ubiquitous sensor network (USN).

• 대한전기학회:학술대회논문집
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• 대한전기학회 2011년도 제42회 하계학술대회
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• pp.1382-1383
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• 2011

결정질 실리콘 태양전지에서 전극 형성 공정은 Voc(Open-circuit voltage), Isc(Short-circuit current), Rser(Series resistance), Rshunt(Shunt resistance), FF(Fill factor) 특성에 영향을 주기 때문에 매우 중요하다. 하지만 paste와 선 공정에서의 조건에 따라 특성이 바뀌기 때문에 소성 공정을 최적화하기는 쉽지 않다. 본 연구에서는 Gravure Off-set printing 방식을 이용하여 결정질 실리콘 기판 표면에 미세 전극 형성 공정을 하고 소성 조건 최적화를 위해 peak 온도와 ramp-up 속도를 변화시켜 각 조건별 특성을 비교하였다. Peak 온도가 커질수록, contact resistance의 감소에 따라 Rser가 줄어들었다. 본 연구를 통해 Voc는 619mV, FF는 77.9%로 측정되는 Gravure Off-set 태양전지에 최적화된 소성 공정 조건을 확보하였다.