• Journal of the Korean Society of Visualization
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• v.20 no.3
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• pp.117-127
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• 2022

The present study has investigated the performance of hydrogen gas generators for inhalation purposes based on polyelectrolyte membrane water electrolysis (PEMWE). The system applied two watering methods. One is pumped water (pumping system) and the other is gravity-fed water without a pump (non-pumping system). The cell efficiencies were compared by measuring the cell voltage and temperature in the hydrogen gas generator, respectively. The results show that the cell voltage and temperature increase with the cell current. The cell temperature is lower in the pumping system than that in the non-pumping system at a given cell current. Even though the amount of hydrogen production is the same regardless of the pumping system, the cell efficiency of the hydrogen gas generator in the non-pumping system is better than that in the pumping system.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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• pp.331-331
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• 2012

With the NAND Flash scaling down, it becomes more and more difficult to follow Moore's law to continue the scaling due to physical limitations. Recently, three-dimensional (3D) flash memories have introduced as an ideal solution for ultra-high-density data storage. In 3D flash memory, as the process reason, we need to use poly-Si TFTs instead of conventional transistors. So, after combining charge trap flash (CTF) structure and poly-Si TFTs, the emerging device SONOS-TFTs has also suffered from some reliability problem such as hot carrier degradation, charge-trapping-induced parasitic capacitance and resistance which both create interface traps. Charge pumping method is a useful tool to investigate the degradation phenomenon related to interface trap creation. However, the curves for charge pumping current in SONOS TFTs were far from ideal, which previously due to the fabrication process or some unknown traps. It needs an optimization and the important geometrical effect should be eliminated. In spite of its importance, it is still not deeply studied. In our work, base-level sweep model was applied in SONOS TFTs, and the nonideal charge pumping current was optimized by adjusting the gate pulse transition time. As a result, after the optimizing, an improved charge pumping current curve is obtained.

• Journal of Power Electronics
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• v.6 no.4
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• pp.298-306
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• 2006

A high efficiency and low cost sustain driver for a plasma display panel (PDP) utilizing a current pumping method is proposed. The main concept of the proposed circuit is using the current source to charge and discharge the panel. As a result, all power switches can achieve zero voltage switching (ZVS) and every auxiliary switch can also achieve zero current switching (ZCS). Since the inductor current can compensate for the discharge current, the current stress of all the power switches can be reduced considerably. Furthermore, it has features such as a simpler structure, less mass, lower cost, and lower electromagnetic interference than in previous circuits.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.50 no.3
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• pp.109-116
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• 2001

In this paper, we adapted BLDC motor to PV water pumping systems to maintain high efficiency in the wide speed area. Also, to design confidence we adapted the vector control that drive the maximum torque at each speed limit. We designed optimal gain value of current, speed and pressure PI controller. Inverter gate pulse used Space Vector PWM to reduce torque pulsation of BLDC motor. According to, it was improve general matters of high water storage tank method by direct water supply pumping method.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.13 no.10
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• pp.822-827
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• 2000

The Si-SiO$_2$interface trap and nitride bulk trap distribution of SONOSFET(polysilicon-oxide-nitride-oxide-semiconductor field effect transistor) NVSM (nonvolatile semiconductor memory) cell is investigated by single junction charge pumping method. The device was fabricated by 0.35㎛ standard logic fabrication process including the ONO stack dielectrics. The thickness of ONO dielectricis are 24$\AA$ for tunnel oxide, 74 $\AA$ for nitride and 25 $\AA$ for blocking oxide, respectively. By the use of single junction charge pumping method, the lateral profiles of both interface and memory traps can be calculated directly from experimental charge pumping results without complex numerical simulation. The interface traps were almost uniformly distributed over the whole channel region and its maximum value was 7.97$\times$10$\^$10/㎠. The memory traps were uniformly distributed in the nitride layer and its maximum value was 1.04$\times$10$\^$19/㎤. The degradation characteristics of SONOSFET with write/erase cycling also were investigated.

• Proceedings of the KIEE Conference
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• 1997.07a
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• pp.244-246
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• 1997

This paper is to analyze the Premature Quench characteristics of a rotating magnet type superconducting fluxpump and consider the method of detecting and protecting this premature quench. Practically, there is contact resistance between the fluxpump and the load, namely the S.C. magnet. The thermal increase due to the contact resistance cause the premature quench before the charging current amounts to the critical current of S.C magnet. Therefore, this paper is devoted to solving the heat equation on contact region using cylindrical coordinates and to calculating the rate of thermal increase during the current is pumped up. Doing so, the predictive value of the maximum pumping current is obtained. It has been verified that the results of simulation are coincident with those of experiment. It must be considered essentially to minimize the contact resistance in designing the S.C fluxpump system in order to protect the premature quench and improve the maximum pumping current.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1999.11a
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• pp.453-456
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• 1999

The Si-SiO$_2$interface trap and nitride bulk trap distribution of SONOSFET(polysilicon-oxide-nitride-oxide-semiconductor)NVSM(nonvolatile semiconductor memory) cell were investigated by single charge pumping method. The used device was fabricated by 0.35 7m standard logic fabrication including the ONO cell process. This ONO dielectric thickness is tunnel oxide 24 $\AA$, nitride 74 $\AA$, blocking oxide 25 $\AA$, respectively. Keeping the pulse base level in accumulation and pulsing the surface into inversion with increasing amplitudes, the charge pumping current flow from the single junction. Using the obtained I$_{cp}$-V$_{h}$ curve, the local V$_{t}$ distribution, doping concentration, lateral interface trap distribution and lateral memory trap distribution were extracted. The maximum N$_{it}$($\chi$) of 1.62$\times$10$^{19}$ /cm$^2$were determined.mined.d.

• Current Optics and Photonics
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• v.6 no.4
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• pp.400-406
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• 2022

We numerically demonstrate that the inherent spiking behavior in the quasi-continuous-wave (QCW) operation of an Nd:YAG laser can be suppressed by adopting bias pumping. After spiking suppression, the output QCW pulses from a bias-pumped Nd:YAG laser are very stable, and they can maintain nearly the same temporal shape as that of pump pulse under different pump repetition rates and peak powers. Our study implies that bias pumping is an alternative method of spiking suppression in solid-state lasers, and the application areas of an Nd:YAG laser may be extended by bias pumping.

• Proceedings of the KIEE Conference
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• 2000.07b
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• pp.1199-1201
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• 2000

This paper proposes a harmonics reducing circuit for fluorescent lamp inverters using hybrid type smoothing circuit with pumping and smoothing capacitors. A waveform of full-wave rectification used as a direct current power supply at fluorescent lamp inverters contains a lot of harmonic wave from inrush current which is generated near the maximum of input voltage with purse shape when voltage smoothing capacitor is charged. Therefore, in order to suppress inrush current which will result in harmonic wave. this paper proposes a method to control abrupt charging current by use of charging voltage at pumping capacitor. The suppression of harmonics generation at lamp current is confirmed through simulations.

• JSTS:Journal of Semiconductor Technology and Science
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• v.14 no.1
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• pp.34-39
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• 2014

This paper discusses the 3-level charge pumping (CP) method in planar-type Silicon-Oxide-High-k-Oxide-Silicon (SOHOS) and Silicon-Oxide-Nitride-Oxide-Silicon (SONOS) devices to find out the reason of the degradation of data retention properties. In the CP technique, pulses are applied to the gate of the MOSFET which alternately fill the traps with electrons and holes, thereby causing a recombination current Icp to flow in the substrate. The 3-level charge pumping method may be used to determine not only interface trap densities but also capture cross sections as a function of trap energy. By applying this method, SOHOS device found to have a higher interface trap density than SONOS device. Therefore, degradation of data retention characteristics is attributed to the many interface trap sites.