• Journal of Korean Society of Water and Wastewater
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• v.31 no.6
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• pp.611-618
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• 2017

Recently, applications of high voltage impulse (hereafter HVI) technique to desalting, sludge solubilization and disinfection have gained great attention. However, information on how the operating condition of HVI changes the water qualities, particularly production of hydroxyl radical (${\cdot}OH$) is not sufficient yet. The aim of this study is to investigate the effect of operating conditions of the HVI on the generation of hydroxyl radical. Indirect quantification of hydroxyl radical using RNO which react with hydroxyl radical was used. The higher HVI voltage applied up to 15 kV, the more RNO decreased. However, 5 kV was not enough to produce hydroxyl radical, indicating there might be an critical voltage triggering hydroxyl radical generation. The concentration of RNO under the condition of high conductivity decreased more than those of the low conductivities. Moreover, the higher the air supplies to the HVI reactor, the greater RNO decreased. The conditions with high conductivity and/or air supply might encourage the corona discharge on the electrode surfaces, which can produce the hydroxyl radical more easily. The pH and conductivity of the sample water changed little during the course of HVI induction.

• Journal of Satellite, Information and Communications
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• v.8 no.1
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• pp.45-53
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• 2013

An electrostatic discharge (ESD) protection device, so called, N-type extended drain silicon controlled rectifier (NEDSCR) device, was analyzed for high voltage I/O applications. A conventional NEDSCR device shows typical SCR-like characteristics with extremely low snapback holding voltage. This may cause latch-up problem during normal operation. However, a modified NEDSCR device with proper junction/channel engineering using counter pocket source (CPS) ion implantation demonstrates itself with both the excellent ESD protection performance and the high latch-up immunity. Since the CPS implant technique does not change avalanche breakdown voltage, this methodology does not reduce available operation voltage and is applicable regardless of the operation voltage.

• Journal of IKEEE
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• v.17 no.1
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• pp.77-82
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• 2013

In this paper, dc-dc buck converter controled by the peak current-mode pulse-width-modulation (PWM) presented. Based on the small-signal model, we propose the novel methods of the power stage and the systematic stability designs. To improve the reliability and performance, over-temperature and over-current protection circuits have been designed in the dc-dc converter systems. To prevent electrostatic An electrostatic discharge (ESD) protection circuit is proposed. The proposed dc-dc converter circuit exhibits low triggering voltage by using the gate-substrate biasing techniques. Throughout the circuit simulation, it confirms that the proposed ESD protection circuit has lower triggering voltage(4.1V) than that of conventional ggNMOS (8.2V). The circuit simulation is performed by Mathlab and HSPICE programs utilizing the 0.35um BCD (Bipolar-CMOS-DMOS) process parameters.

• Biomolecules & Therapeutics
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• v.1 no.2
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• pp.171-176
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• 1993

Purpose of the present study was to clarify the role of noradrenergic neural activities in hypothalamus for either triggering or maintaining hypertension in deoxycorticosterone (DOCA)-salt hypertensive rats. Two groups of animals were prepared: 1) normotensive Wistar rats and 2) DOCA-salt induced hypertensive rats. Voltage dependent $^{45}Ca^{++}$ uptake, endogenous norepinephrine release, and the catecholamine content in the hypothalamus of DOCA-salt hypertensive and normotensive Wistar rats were compared. Animals at 4, 6 and 16 week-old of two groups were sacrificed by decapitation and hypothalamus was dissected out. Voltage dependent calcium uptake and norepinephrine release were determined from hypothalamic synaptosomes either in low potassium or high potassium stimulatory condition by using $^{45}Ca^{++}$ isotope and HPLC-ECD technique. Degrees of voltage dependent $^{45}Ca^{++}$ uptake and norepinephrine release in hypothalamic synaptosomes of 16-week-old DOCA-salt hypertensive rats were significantly greater than those of age matched normotensive control rats. The norepinephrine and dopamine contents of hypothalamus were about the same in two groups of animals. These results suggest that the alteration of evoked norepinephrine release related to calcium uptake in hypothalamus may play a role in the maintenance of hypertension in DOCA-salt hypertensive rats.

• Journal of IKEEE
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• v.18 no.1
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• pp.25-30
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• 2014

In this paper, SCR(Silicon Controlled Rectifier)-based ESD(Electrostatic Discharge) protection circuit for power clamp is proposed. In order to improve latch-up immunity caused by low holding voltage of the conventional SCR, it is modified by inserting n+ floating region and n-well, and extending p+ cathode region in the p-well. The resulting ESD capability of our proposed ESD protection circuit reveals a high latch-up immunity due to the high holding voltage. It is verified that electrical characteristics of proposed ESD protection circuit by Synopsys TCAD simulation tool. According to the simulation results, the holding voltage is increased from 4.61 V to 8.75 V while trigger voltage is increased form 27.3 V to 32.71 V, respectively. Compared with the conventional SCR, the proposed ESD protection circuit has the high holding voltage with the same triggering voltage characteristic.

• Journal of the Korean Society of Safety
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• v.28 no.3
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• pp.51-55
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• 2013

The purpose of this study is to find the causes of malfunctions and defective operation of printed circuit boards(PCBs) built into home refrigerators to perform power saving functions. This study performed an electrostatic test of a PCB built-in using an Auto Triggering system; lightning and impulse tests using an LSS-15AX; and an impulse test using an INS-400AX. From the analysis of a secondarily developed product, it was found that electrostatic discharge(ESD) caused more malfunctions and defective operations than electric overstress(EOS) due to overvoltage. As a result of increasing the condenser capacity of the PCB circuit, withstanding voltage was increased to 7.4 kV. In addition, this study changed the power saving mode and connected a varistor to the #2 pin of an IC chip. As a result, the system consisting of all specimens of a finally developed product was operated stably with an applied voltage of less than 10 kV. This study found it necessary to perform quality control at the manufacturing stage in order to reduce the occurrence of electrostatic accidents to IC chips built into a PCB.

• Proceedings of the Korean Society of Medical Physics Conference
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• 2002.09a
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• pp.396-399
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• 2002

Intense quasi-monochromatic x-ray irradiation from the linear plasma target is described. The plasma x-ray generator employs a high-voltage power supply, a low-impedance coaxial transmission line, a high-voltage condenser with a capacity of about 200 nF, a turbo-molecular pump, a thyristor pulse generator as a trigger device, and a flash x-ray tube. The high-voltage main condenser is charged up to 55 kV by the power supply, and the electric charges in the condenser are discharged to the tube after triggering the cathode electrode. The x-ray tube is of a demountable triode that is connected to the turbo molecular pump with a pressure of approximately 1 mPa. As electron flows from the cathode electrode are roughly converged to the molybdenum target by the electric field in the tube, the weakly ionized plasma, which consists of metal ions and electrons, forms by the target evaporating. In the present work, the peak tube voltage was almost equal to the initial charging voltage of the main condenser, and the peak current was about 20 kA with a charging voltage of 55 kV. When the charging voltage was increased, the linear plasma x-ray source grew, and the characteristic x-ray intensities of K-series lines increased. The quite sharp lines such as hard x-ray lasers were clearly observed. The quasi-monochromatic radiography was performed by a new film-less computed radiography system.

• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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• v.3B no.1
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• pp.10-15
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• 2003

This paper presents the digital computer performance evaluations of the three-phase self-excited induction generator (SEIG) driven by the variable speed prime mover such as the wind turbine using the nodal admittance approach steady-state frequency domain analysis with the experimental results. The three-phase SEIG setup is implemented for small-scale rural renewable energy utilizations. The experimental performance results give a good agreement with those ones obtained from the digital computer simulation. Furthermore, a feedback closed-loop voltage regulation of the three-phase SEIG as a power conditioner which is driven by a variable speed prime mover employing the static VAR compensator (SVC) circuit composed of the thyristor phase controlled reactor (TCR) and the thyristor switched capacitor(TSC) is designed and considered herein for the wind-turbine driven the power conditioner. To validate the effectiveness of the SVC-based voltage regulator of the terminal voltage of the three-phase SEIG, an inductive load parameter disturbances in stand-alone are applied and characterized in this paper. In the stand-alone power utilization system, the terminal voltage response and thyristor triggering angle response of the TCR are plotted graphically. The simulation and the experimental results prove the effectiveness and validity of the proposed SVC which is controlled by the Pl controller in terms of fast response and high performances of the three-phase SEIG driven directly by the rural renewable energy utilization like a variable-speed prime mover.

• Journal of Satellite, Information and Communications
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• v.7 no.2
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• pp.18-24
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• 2012

High current behaviors of the extended drain n-type metal-oxide-semiconductor field effects transistor (EDNMOSFET) for electrostatic discharge (ESD) protection of high voltage operating LDI (LCD Driver IC) chip are analyzed. Both the transmission line pulse (TLP) data and the thermal incorporated 2-dimensional simulation analysis demonstrate a characteristic double snapback phenomenon after triggering of biploar junction transistor (BJT) operation. Also, background doping concentration (BDC) is proven to be a critical factor to affect the high current behavior of the EDNMOS devices. The EDNMOS device with low BDC suffers from strong snapback in the high current region, which results in poor ESD protection performance and high latchup risk. However, the strong snapback can be avoided in the EDNMOS device with high BDC. This implies that both the good ESD protection performance and the latchup immunity can be realized in terms of the EDNMOS by properly controlling its BDC.

• Transactions on Electrical and Electronic Materials
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• v.7 no.1
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• pp.1-6
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• 2006

Hot carrier degradation and roll off characteristics of threshold voltage ($V_{t1}$) on NMOSFETs as I/O transistor are studied as a function of Lightly Doped Drain (LDD) structures. Pocket dose and the combination of Phosphorus (P) and Arsenic (As) dose are applied to control $V_{t1}$ roll off down to the $10\%$ gate length margin. It was seen that the relationship between $V_{t1}$ roll off characteristic and substrate current depends on P dopant dose. For the first time, we found that the n-p-n transistor triggering voltage ($V_{t1}$) depends on drain current, and both $I_{t2}$ and snapback holding voltage ($V_{sp}$) depend on the substrate current by characterization with a transmission line pulse generator. Also it was found that the improved lifetime for hot carrier stress could be obtained by controlling the P dose as loosing the $V_{t1}$ roll off margin. This study suggests that the trade-off characteristic between gate length margin and channel hot carrier (CHC) lifetime in NMOSFETs should be determined by considering Electrostatic Discharge (ESD) characteristic.