• Journal of the Institute of Electronics Engineers of Korea SD
• /
• v.45 no.5
• /
• pp.50-57
• /
• 2008

In this paper, a high-efficiency charge pump for use in CMOS image sensor(CIS) is proposed. The proposed charge pump pursues high pumping efficiency by minimizing the switching and reversion losses by taking advantage of operation characteristics of CIS. That is, the proposed charge pump minimizes the switching loss by dynamically controlling the size of clock driver, pumping capacitor, and charge transfer switch based on the operation phase of CIS pixel sensor. The charge pump also minimizes the reversion loss by guaranteeing a sufficient non-overlapping period of local clocks using a tri-state local clock driver adapting the schmitt trigger. Comparison results using a 0.13-um CMOS process technology indicate that the proposed charge pump achieves up to 49.1% reduction on power consumption under no loading current condition as compared to conventional charge pump. They also indicate that the charge pump provides 19.0% reduction on power consumption under the maximum loading current condition.

• Proceeding of Spring/Autumn Annual Conference of KHA
• /
• 2002.11a
• /
• pp.89-95
• /
• 2002

The purpose of this study is to assess the residential satisfaction of no-charge welfare facility for the elderly, and to examine the effect of the integration with pay-training institute on residential satisfaction. The data were collected from staffs and fifty one residents of welfare facility by interview and questionnaire. The statistical analysis was conducted to identify the residential satisfaction. A half of the elderly were aged over seventy five years old, eighty four percents of them were female, and seventy seven percents of them were non-educated. Forty two percents of the elderly considered themselves to be unhealthy, but the ADL data reveals that they are relatively healthy. The most of residents are highly satisfied with whole welfare facility. But, the level of satisfaction on the bathroom, the storing space, the cooking table and the benches were relatively low. These dissatisfactions can be solved by the expanding of the storing space, setting up of a common washing room and electric cooking stove, and the increasing of the number of benches. Also, it was recommended for the elderly to set up the Ondol-style rest room with the western style rest room. The level of satisfaction on the attached training institute with no-charge welfare facility for the elderly were high. This has positive effect on residential satisfaction of the elderly. Therefore, the community integrated welfare facility can be the alternative plan for the enhancement of residential satisfaction and quality of elderly life.

• Transactions of Materials Processing
• /
• v.32 no.4
• /
• pp.191-198
• /
• 2023

We examined the martensitic transformation kinetics for metastable stainless steel during electrochemical polishing (EP) using different types of electrolytes. Martensite fraction measured with EBSD showed that the electrolyte with high relative permittivity exhibited comparably higher levels of martensitic transformation. The amount of charge build-up on the specimen surface during EP with different types of electrolytes was calculated using COMSOL multiphysics simulations to understand these phase transformation characteristics. The effect of charge build-up-induced stress was analyzed using previously published first-principles calculations. We discovered that the electrolyte with high relative permittivity accumulated a greater amount of charge build-up, resulting in a stronger driving force for stress-induced martensitic transformation.

• JSTS:Journal of Semiconductor Technology and Science
• /
• v.14 no.3
• /
• pp.331-338
• /
• 2014

A charge-pump circuit using a current-bypass technique, which suppresses charge sharing and reduces the sub-threshold currents, helps to decrease phase-locked loop (PLL) jitter without resorting to a feedback amplifier. The PLL shows no stability issues and no power-up problems, which may occur when a feedback amplifier is used. The PLL is implemented in 0.11-${\mu}m$ CMOS technology to achieve 0.856-ps RMS and 8.75-ps peak-to-peak jitter, which is almost independent of ambient temperature while consuming 4 mW from a 1.2-V supply.

• Journal of Microbiology and Biotechnology
• /
• v.5 no.3
• /
• pp.163-166
• /
• 1995

Chemical modification of gelatin-based macroporous microcanier beads was achieved by increasing the charge density through incorporation of (diethylamino)ethylchloride-hydrochloride (DEAE:CI-HCI) or lysine, and this significantly improved the attachment and growth of HepG2 cells. When microcarriers were modified by the addition of 2% lysine, positive charge density was 0.95 meq/g-caniers. In case of modification of microcarriers with DEAE:CI-HCI, positive charge density was 0.6 meq/g-caniers. An increase in charge density of the microcaniers to improve cell attachment has facilitated the growth of the cells on macroporous gelatin microcaniers. Also, final HepG2 cell concentration cultivated on modified beads with DEAE:CI-HCI was increased up to $10^7$ cells/ml. This was 2-3 times higher than that obtained with unmodified macroporous gelatin microcarriers.

• Journal of Environmental Health Sciences
• /
• v.35 no.1
• /
• pp.64-70
• /
• 2009

The aims of this study is to examine the effects of the changes in HRT(Hydraulic Retention Time) and media charge in a water-mill, among other operation factors, on the nitrogen and phosphorus removal in order to use up-flow anaerobic reactors, anoxic reactors and water-mill aerobic reactors for sewage treatment. The extension of HRT improved the nitrogen removal efficiency, however the removal pattern was constant regardless of HRT. The removal of phosphorus was constant (80%-90%) regardless of the change in HRT. The removal rate with change in influx load varied such that at the OLR (Organic Load Rate) of 1-3 kg/d, the T-N removal efficiency was 80.7%-88.9% and the T-P removal efficiency was 82.9%-89.3% while at the NLR (Nitrogen Loading Rate) of 0.108-0.156 kg/d the removal efficiencies were 80.7-88.9% (T-N) and 82.9-89.3% (T-P). The analyses of the nitrogen and phosphorous removal characteristics with the C/N and C/P ratio showed that the mean T-N removal rate was 88% at the C/N ratio of 1.2-2.6, and that the mean T-P removal rate was 86% at the C/P ratio of 7.2-14.1. Also, the analysis of nitrogen and phosphorous removal characteristics were analyzed in relation to media charge. The comparison between with and without media charge in the water-mill showed that while the nitrogen removal efficiencies were 86-94% and 85-89% respectively, the difference of phosphorous removal efficiencies were between the two conditions was not significant, thus it suggested that the media charge has less effect on the removal efficiency of phosphorous compared to that of nitrogen.

• JSTS:Journal of Semiconductor Technology and Science
• /
• v.17 no.2
• /
• pp.167-173
• /
• 2017

In this paper, the characterization of the vertical position of trapped charges in the charge-trap flash (CTF) memory is performed in the novel CTF memory cell with gate-all-around structure using technology computer-aided design (TCAD) simulation. In the CTF memories, injected charges are not stored in the conductive poly-crystalline silicon layer in the trapping layer such as silicon nitride. Thus, a reliable technique for exactly locating the trapped charges is required for making up an accurate macro-models for CTF memory cells. When a programming operation is performed initially, the injected charges are trapped near the interface between tunneling oxide and trapping nitride layers. However, as the program voltage gets higher and a larger threshold voltage shift is resulted, additional charges are trapped near the blocking oxide interface. Intrinsic properties of nitride including trap density and effective capture cross-sectional area substantially affect the position of charge centroid. By exactly locating the charge centroid from the charge distribution in programmed cells under various operation conditions, the relation between charge centroid and program operation condition is closely investigated.

• 한국태양에너지학회:학술대회논문집
• /
• 2011.04a
• /
• pp.68-73
• /
• 2011

An experimental study was conducted to investigate the thermal performance of a medium-temperature heat pipe against the charge amount of working fluid. The container and the wick of the heat pipe were made of stainless steel and the working fluid was Dowtherm-A for medium-temperature applications around $250^{\circ}C$. The diameter and length of the heat pipe were 25.4 mm and 1 m, respectively. The maximum thermal load was 1 kW and the working fluid charge ratio varied from 372% to 420%. The results showed that the thermal resistance ranged from 0.12 to $250^{\circ}C/W$ and the effective thermal conductance ranged from 7,703 to $8,898 W/m{\cdot}K$. Dry-out occurred for the heat pipe with 372% fill-charge at the heat load of 950 W, while the other heat pipes with higher charge amount did not encounter dry-out up to 1060 W.

• Journal of Powder Materials
• /
• v.6 no.1
• /
• pp.69-74
• /
• 1999

The microstructure of the reagion of carters, created by Cu and W-Cu shaped charge jets, in a 1020 mild steel target has been intestiaged. The region ahead of the crater created by the Cu shaped charge jet, reveals dramatic grain refinement implying the occurrence of a dynamic recrystallization, while that of W-Cu one dose a martensitic transformation indicative of heating up to an austenitic region followed by rapid cooling.The impacting pressure calculated when the W-Cu shaped charge jet encounters the target is higher than that of the Cu one. The micro-hardness of the region ahead of the crater created by the W-Cu shaped charge jet is also higher than that of the Cu one. The microstructure of W-Cu slug remained in the inside of the craters depicts the occurrence of the remarkable elongation of W particles during the liner collaphse. From these results, the microstructural variation of the region ahead of the crater with Cu and W-Cu shaped charge jets is discussed in trems of the pressure dependency of the transformation region of ferrite and austenite phases.

• Journal of the Korean Ceramic Society
• /
• v.37 no.2
• /
• pp.128-133
• /
• 2000

In this work, soft carbons produced by pyrolysis of petroleum and coal-tar pitch were used as the negative electrode for Li-ion batteries. We studeid the charge/discharge capacity and the interfacial reaction of these electrodes by constructing a half cell. Charge/discharge property was studied by a constant-current step and the interfacial reaction between the electrolyte and the surface of a carbon electrode was studied by the cyclic voltammetry. The initial charge/discharge capacity for the coal-tar pitch carbon increased exceedingly with the heat treatment temperature. On hte other hand, the capacity of the petroleum pitch carbon increased with temperature up to 1000$^{\circ}C$, thereafter decreased continuously. While the charge capacity decreased with the cycle number, the reversibility increased above 90%. In addition, the thermal stability and crystallization of petroleum and coal-tar pitches were analyzed by TGA and XRD, respectively.