• 한국정보통신학회논문지
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• 제10권9호
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• pp.1625-1632
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• 2006

시술자로부터 침을 경유하여 유도되는 전위는 피시술자의 경락 경혈에서 전위변화의 원인으로 중요한 요소이다. 이에 대하여, 족양명위경상의 족삼리(ST36)에서 다양한 수기자극 방식에 따라 상거허혈(ST37)과 하거허혈(ST39)에서 유발되는 경락전위 패턴을 관찰하였다. 수기자극에 대한 임상실험결과, 침치료에 있어서 다양한 수기자극조건은 주로 톱니파(용량성 전류) 형태의 전위파형이 관찰되었다. 따라서 시술자와 피시술자간의 침치료 효과에 영향을 주는 주된 자극패턴은 용량성 전류자극 패턴임을 확인하였다.

• 한국광학회:학술대회논문집
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• 한국광학회 1991년도 제6회 파동 및 레이저 학술발표회 Prodeedings of 6th Conference on Waves and Lasers
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• pp.135-138
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• 1991

A planar type PIN photodiode has been fabricated and discussed. We used OMVPE systems to grow the structure of u-InP/u-InP/n-InP. P-n junction was formed by Zn-diffusion method at 50$0^{\circ}C$, for 5 minitues. The device characteristics at 5V were as follows: Dark currents were distributed around 1nA. Capacitance was 1.6pF and responsivity was above 0.85 mA/mW for 1.3${\mu}{\textrm}{m}$ wavelength. Measured cut-off frequency(-3dB) at -5V was 1.1㎓.

• Journal of Power Electronics
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• 제13권3호
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• pp.329-338
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• 2013

In this paper, the charging characteristics of series resonant type high voltage capacitor chargers considering the transformer stray capacitance have been studied. The principles of operation for the four operational modes and the mode changes for the four different switching frequency sections are explained and analyzed in the range of switching frequency below the resonant frequency. It is confirmed that the average charging currents derived from the above analysis results have non-linear characteristics in each of the four modes. The resonant current, resonant voltage, charging current, and charging time of this capacitor charger as variations of the switching frequency, series parallel capacitance ratio ($k=C_p/C_s$), and output voltage are calculated. From the calculation results, the advantages and disadvantages arising from the parallel connection of this stray capacitance are described. Some methods to minimize charging time of this capacitor charger are suggested. In addition, the results of a comparative test using two transformers whose stray capacitances are different are described. A 1.8 kJ/s prototype capacitor charger is assembled with a TI28335 DSP controller and a 40 kJ, 7 kV capacitor. The analysis results are verified by the experiment.

• Bulletin of the Korean Chemical Society
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• 제20권9호
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• pp.1049-1055
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• 1999

Electrochemical oxidation of silicon (p-type Si(100)) at room temperature in ethylene glycol and in aqueous solutions has been performed by applying constant low current densities for the preparation of thin SiO2 layers. In-situ ac impedance spectroscopic methods have been employed to characterize the interfaces of electrolyte/oxide/semiconductor and to estimate the thickness of the oxide layer. The thicknesses of SiO2 layers calculated from the capacitive impedance were in the range of 25-100Å depending on the experimental conditions. The anodic polarization resistance parallel with the oxide layer capacitance increased continuously to a very large value in ethylene glycol solution. However, it decreased above 4 V in aqueous solutions, where oxygen evolved through the oxidation of water. Interstitially dissolved oxygen molecules in SiO2 layer at above the oxygen evolution potential were expected to facilitate the formation of SiO2 at the interfaces. Thin SiO2 films grew efficiently at a controlled rate during the application of low anodization currents in aqueous solutions.

• 전자공학회논문지A
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• 제30A권8호
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• pp.34-41
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• 1993

Effect of high temperature annealing conditions on Ta$_{2}O_{5}$ thin films was investigated. Ta$_{2}O_{5}$ thin films were deposited on P-type silicon substrates by plasma-enhanced chemical vapor deposition (PECVD) using tantalum ethylate. Ta(C$_{2}H_{5}O)_{5}$, and nitrous oxide. N$_{2}$O. The microstructure changed from amorphous to polycrystalline above 700.deg. C annealing temperature. The refractive index, dielectric onstant and leakage current of the film increased as annealing temperature increased. However, annealing in oxygen ambient reduced leakage currents and dielectric constant due to the formation of interfacial SiO$_{2}$ layer. By optimizing annealing temperature and ambient, leakage current lower than 10$^{-8}$ A/cm$^{2}$ and maximum capacitance of 9 fF/${\mu}m^{2}$ could be obtained.

• 조명전기설비학회논문지
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• 제19권4호
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• pp.71-78
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• 2005

본 연구는 AC PDP(Plasma Display Panel)용 멀티레벨 에너지 회수회로에 관한 연구로서, 기존 멀티레벨 구동회로의 문제점을 해결한 새로운 멀티레벨 구동회로를 제안한다. 기존 멀티레벨 구동회로는 Weber회로에서 나타나는 스위칭 소자의 전압 및 전류 스트레스를 개선하였지만 공진 인덕터와 기생 커패시턴스에 의한 기생공진전류가 존재하고 하드스위칭이 발생하며 또한 천이구간이 다소 긴 문제점이 있다. 제안 회로는 사용소자의 수를 줄여 회로를 간단히 하였으며, 기생공진전류를 제거하여 회로 동작의 안정성을 높였다. 또한 CIM(Current Injection Method) 을 사용하여 하드스위칭 문제를 해결하였으며 Vs/2 유지구간을 제거하여 동작주파수를 증가시킬 수 있도록 하였다. 제안 회로의 유용성을 입증하기 위해 모드별로 동작을 해석하였으며, PSpice프로그램을 이용하여 시뮬레이션하고 그 결과를 확인하였다.

• 한국의학물리학회:학술대회논문집
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• 한국의학물리학회 2003년도 제27회 추계학술대회
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• pp.45-45
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• 2003

The aim of this study was the characterization and performance validation of new prototype avalanche photodiode (APD) arrays for positron emission tomography (PET). Two different APD array prototypes (noted A and B) developed by Radiation Monitoring Device (RMD) have been investigated. Principal characteristics of the two APD array were measured and compared. In order to characterize and evaluate the APD performance, capacitance, doping concentration, quantum efficiency, gain and dark current were measured. The doping concentration that shows the impurity distribution within an APD pixel as a function of depth was derived from the relationship between capacitance and bias voltage. Quantum efficiency was measured using a mercury vapor light source and a monochromator used to select a wavelength within the range of 300 to 700 nm. Quantum efficiency measurements were done at 500 V, for which the APD gain is equal to one. For the gain measurements, a pencil beam with 450 nm in wavelength was illuminating the center of each pixel. The APD dark currents were measured as a function of gain and bias. A linear fitting method was used to determine the value of surface and bulk leakage currents. Mean quantum efficiencies measured at 400 and 450 nm were 0.41 and 0.54, for array A, and 0.50 and 0.65 for array B. Mean gain at a bias voltage of 1700 V, was 617.6 for array A and 515.7 for type B. The values based on linear fitting were 0.08${\pm}$0.02 nA 38.40${\pm}$6.26 nA, 0.08${\pm}$0.0l nA 36.87${\pm}$5.19 nA, and 0.05${\pm}$0.00 nA, 21.80${\pm}$1.30 nA in bulk surface leakage current for array A and B respectively. Results of characterization demonstrate the importance of performance measurement validating the capability of APD array as the detector for PET imaging.

• Journal of the Optical Society of Korea
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• 제16권1호
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• pp.1-5
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• 2012

This paper describes a 150-Mb/s monolithic optical receiver for plastic optical fiber link using a standard CMOS technology. The receiver integrates a photodiode using an N-well/P-substrate junction, a pre amplifier, a post amplifier, and an output driver. The size, PN-junction type, and the number of metal fingers of the photodiode are optimized to meet the link requirements. The N-well/P-substrate photodiode has a 200-${\mu}m$ by 200-${\mu}m$ optical window, 0.1-A/W responsivity, 7.6-pF junction capacitance and 113-MHz bandwidth. The monolithic receiver can successfully convert 150-Mb/s optical signal into digital data through up to 30-m plastic optical fiber link with -10.4 dBm of optical sensitivity. The receiver occupies 0.56-$mm^2$ area including electrostatic discharge protection diodes and bonding pads. To reduce unnecessary power consumption when the light is not over threshold or not modulating, a simple light detector and a signal detector are introduced. In active mode, the receiver core consumes 5.8-mA DC currents at 150-Mb/s data rate from a single 3.3 V supply, while consumes only $120{\mu}W$ in the sleep mode.

• 한국산학기술학회논문지
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• 제22권2호
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• pp.810-818
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• 2021

ESS의 누설전류는 PCS(Power Control System)측 누설전류와 계통불평형 전류로 인한 누설전류로 구분되는데, PCS측의 누설전류는 정상 상태 운전 시, IGBT(Insulated Gate Bipolar Transistor) 스위칭의 전압 변화량과 IGBT와 방열판 사이에 존재하는 기생 커패시턴스에 의해 발생한다. 또한, 계통불평형 전류에 의한 누설전류는 불평형 부하로 인해 발생한 불평형 전류가 Yg-∆ 결선방식의 3각 철심이 적용된 태양광전원 연계형 변압기의 중성선을 통해 ESS로 유입된다. 따라서, 본 논문에서는 방열판 유도공식을 통해 산정한 기생 커패시턴스에 의하여 PCS측의 누설전류 발생 메커니즘을 제시하고 또한, 계통불평형에 의한 ESS측의 누설전류 발생 메커니즘을 제안한다. 이를 바탕으로, 배전계통 상용해석 프로그램인 PSCAD/EMTDC를 이용하여 배터리부, PCS부, AC전원부로 이루어진 PCS측의 누설전류 발생 메커니즘과 배전 계통부, 불평형 부하부, ESS부로 이루어진 계통불평형에 의한 ESS측의 누설전류 발생 메커니즘을 모델링하고, 누설전류의 특성을 평가한다. 상기의 모델링을 바탕으로 시뮬레이션을 수행한 결과, 외함의 저항과 접지저항의 크기에 따라 PCS측의 누설전류는 7[mA]에서 34[mA]로, 계통불평형에 의한 배터리 외함으로 흐르는 누설전류는 3.96[mA]에서 10.76[mA]로 증가하여 배터리측에 큰 영향을 미침을 알 수 있었다.

• 대한수의학회지
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• 제40권2호
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• pp.275-282
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• 2000

Substantia nigra is known to highly express glibenclamide binding site, a protein associated to ATP-sensitive $K^{+}$ ($K_{ATP}$) channel in the brain. However, the functional expression of $K_{ATP}$ channels in the area is not yet known. In this work, we attempted to estimate the functional expression of $K_{ATP}$ channels in neurons of the substantia nigra pars compacta (SNC) in young rats using slice patch clamp technique. Membrane properties and whole cell currents attributable to $K_{ATP}$ channel were examined by the current and voltage clamp method, respectively. In SNC, two sub-populations of neurons were identified. Type I (rhythmic) neurons had low frequency rebound action potentials ($4.5{\pm}0.25Hz$, n=75) with rhythmic pattern. Type II (phasic) neurons were characterized by faster firing ($22.7{\pm}3.16Hz$, n=12). Both time constants and membrane capacitance in rhythmic neurons ($34.0{\pm}1.27$ ms, $270.0{\pm}11.83$ pF) and phasic neurons ($23.7{\pm}4.16$ ms, $184{\pm}35.2$ pF) were also significantly different. The current density of $K_{ATP}$ channels was $6.1{\pm}1.47$ pA/pF (2.44~15.43 pA/pF, n=8) at rhythmic neurons of young rats. Our data show that in SNC there are two types of neurons with different electrical properties and the density of $K_{ATP}$, channel of rhythmic neuron is about 600 channels per neuron.