• Journal of information and communication convergence engineering
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• 제7권3호
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• pp.361-365
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• 2009

This paper has been presented the transport characteristics of FinFET using the analytical potential model based on the Poisson's equation in subthreshold and threshold region. The threshold voltage is the most important factor of device design since threshold voltage decides ON/OFF of transistor. We have investigated the variations of threshold voltage and drain induced barrier lowing according to the variation of geometry such as the length, width and thickness of channel. The analytical potential model derived from the three dimensional Poisson's equation has been used since the channel electrostatics under threshold and subthreshold region is governed by the Poisson's equation. The appropriate boundary conditions for source/drain and gates has been also used to solve analytically the three dimensional Poisson's equation. Since the model is validated by comparing with the three dimensional numerical simulation, the subthreshold current is derived from this potential model. The threshold voltage is obtained from calculating the front gate bias when the drain current is $10^{-6}A$.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 1999년도 제30회 추계학술대회
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• pp.184-189
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• 1999

This Paper presents the friction and lubrication charateristic related with oil aeration. It is well known that oil aeration occurs severe problem on lubrication system, in particular, in the engine bearings and hydraulic lash adjuster. In this study, engine tests were carried out in motoring conditions. In order to investigate oil aeration characteristics, we measured oil aeration with respect to oil temperature, oil viscosity, modified oil drain system. From the results, we concluded that aeration can be reduced by improving oil drain system and FMEP can be reduced by minimising of aeration.

• 한국광학회:학술대회논문집
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• 한국광학회 2000년도 하계학술발표회
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• pp.162-163
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• 2000

We have observed the short-channel effect, narrow-channel effect and small-geometry effect in terms of a variation of the threshold voltage. For a short-channel effect the threshold voltage was largely determined by the DIBL effect which stimulates more carrier injection in the channel by reducing the potential barrier between the source and channel. The effect becomes more significant for a shorter-channel device. However, the potential, field and current density distributions in the channel along the transverse direction showed a better uniformity for shorter-channel devices under the same voltage conditions. The uniformity of the current density distribution near the drain on the potential minimum point becomes worse with increasing the drain voltage due to the enhanced DIBL effect. This means that considerations for channel-width effect should be given due to the variation of the channel distributions for short-channel devices. For CCDs which are always operated at a pinch-off state the channel uniformity thus becomes significant since they often use a device structure with a channel length of > 4 ${\mu}{\textrm}{m}$ and a very high drain (or diffusion) voltage. (omitted)

• 산업기술연구
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• 제29권A호
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• pp.127-134
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• 2009

In this paper, an numerical approach is performed to investigate the effects of smear zone, occurred by penetrating vertical drains, on consolidation behavior of soft clay deposits. Such a numerical analysis is applied to the field condition to confirm its applicability. Parametric numerical analyses is carried out to study influencing factors such as permeability in smear zone, boundary of smear zone and discharge capacity of vertical drains on the consolidation of soil. As results of analyses, for the given conditions of soil, degree of consolidation is getting faster with increase of permeability of vertical drain. Degree of consolidation is delayed with decrease of permeability of smear zone. As the ratio of drain width to smear zone increases, the degree of consolidation decreases. Proposed values of influencing factors by previous researchers is found to be reliable from results of numerical analyses with Cam-clay model.

• 한국전기전자재료학회논문지
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• 제11권10호
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• pp.918-923
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• 1998

Poly-silicon thin film transistors were fabricated on quartz substrates by high temperature processes. Electrical characteristics were measured and compared for 3 transistor structures of Standard Inverted Gate(SIG), Lightly Doped Drain(LDD), and Dual Gate(DG). Leakage currents of DG and LDD TFT's were smaller that od SIG transistor, while ON-current of LDD transistor is much smaller than that of SIG and DG transistors. Temperature dependence of the leakage currents showed that SIG and DG TFT's had thermal generation current at small drian bias and Frenkel-Poole emission current at hight gate and drain biases, respectively. In case of LDD transistor, thermal generation was the dominant mechanism of leakage current at all bias conditions. It was found that the leakage current was closely related to the reduction of the electric field in the drain depletion region.

• 한국지반신소재학회논문집
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• 제15권2호
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• pp.35-44
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• 2016

PET 인공골재의 배수특성 평가를 위하여 실내 수평투수실험, 실대형 수평투수실험을 실시하였다. 실내 수평투수실험은 PET 골재의 생산량에 따라 세 종류의 입도별로 분류하고, 분류된 PET 골재를 정해진 배합비에 의해 20가지로 분류하여 단계별 하중을 재하하면서 실시하였다. 또한 실내 수평투수실험에 의해 분석된 결과를 활용하여 재하하중에 따른 투수계수의 변화경향이 가장 적은 실험 유형의 배합비로 실대형 수평투수실험을 실시하였고, 실내 수평투수실험 결과와 비교하여 신뢰도를 평가하였다.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2009년도 제38회 동계학술대회 초록집
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• pp.140-140
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• 2010

Non-mass analyzed ion shower doping (ISD) technique with a bucket-type ion source or mass-analyzed ion implantation with a ribbon beam-type has been used for source/drain doping, for LDD (lightly-doped-drain) formation, and for channel doping in fabrication of low-temperature poly-Si thin-film transistors (LTPS-TFT's). We reported an abnormal activation behavior in boron doped poly-Si where reverse annealing, the loss of electrically active boron concentration, was found in the temperature ranges between $400^{\circ}C$ and $650^{\circ}C$ using isochronal furnace annealing. We also reported reverse annealing behavior of sequential lateral solidification (SLS) poly-Si using isothermal rapid thermal annealing (RTA). We report here the importance of implantation conditions on the dopant activation. Through-doping conditions with higher energies and doses were intentionally chosen to understand reverse annealing behavior. We observed that the implantation condition plays a critical role on dopant activation. We found a certain implantation condition with which the sheet resistance is not changed at all upon activation annealing.

• 한국식품조리과학회지
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• 제28권5호
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• pp.599-604
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• 2012

In this study, the prevalence of microbiological hazard on water purifiers at lunchroom in child care center was investigated. A total of 49 water purifiers and their purified cold water were sampled to test about the total aerobic bacteria, coliform bacteria, Bacillus cereus, Staphylococcus aureus, and Salmonella spp. Total aerobic bacteria was detected over 2.0 log CFU/mL in 6 out of 49 purified cold water (12.2%), ranged from 2.0 to 2.4 log CFU/mL, and the average number of total aerobic bacteria was showed to be 3.3 log CFU/drain spout. The drain spout turned out to be a major contaminant in water purifier and needs to be improved. Coliform bacteria were also detected in 7 out of 49 cold faucets (14.3%) and 7 out of 49 drain spouts (14.3%), but not detected in purified cold water. All samples were not contaminated with the pathogens tested in this study, except for B. cereus, which was contaminated on 2 out of 49 cold faucets (4.1%) and 4 out of 49 drain spouts (8.2%). All of B. cereus isolates produced enterotoxin, such as heamolysin BL enterotoxin (HBL) or non-heamolytic enterotoxin (NHE). The HBL was detected in 5 out of 6 B. cereus isolates (83.3%), including B. cereus PCF-11 and B. cereus PDS-30 isolate only produced NHE (16.7%). These results showed that the sanitary conditions of cold faucets and drain spouts should be improved promptly.

• JSTS:Journal of Semiconductor Technology and Science
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• 제7권3호
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• pp.196-208
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• 2007

An analytical model is proposed for an optically controlled Metal Semiconductor Field Effect Transistor (MESFET), known as Optical Field Effect Transistor (OPFET) considering the diffusion fabrication process. The electrical parameters such as threshold voltage, drain-source current, gate capacitances and switching response have been determined for the dark and various illuminated conditions. The Photovoltaic effect due to photogenerated carriers under illumination is shown to modulate the channel cross-section, which in turn significantly changes the threshold voltage, drainsource current, the gate capacitances and the device switching speed. The threshold voltage $V_T$ is reduced under optical illumination condition, which leads the device to change the device property from enhancement mode to depletion mode depending on photon impurity flux density. The resulting I-V characteristics show that the drain-source current IDS for different gate-source voltage $V_{gs}$ is significantly increased with optical illumination for photon flux densities of ${\Phi}=10^{15}\;and\;10^{17}/cm^2s$ compared to the dark condition. Further more, the drain-source current as a function of drain-source voltage $V_{DS}$ is evaluated to find the I-V characteristics for various pinch-off voltages $V_P$ for optimization of impurity flux density $Q_{Diff}$ by diffusion process. The resulting I-V characteristics also show that the diffusion process introduces less process-induced damage compared to ion implantation, which suffers from current reduction due to a large number of defects introduced by the ion implantation process. Further the results show significant increase in gate-source capacitance $C_{gs}$ and gate-drain capacitance $C_{gd}$ for optical illuminations, where the photo-induced voltage has a significant role on gate capacitances. The switching time ${\tau}$ of the OPFET device is computed for dark and illumination conditions. The switching time ${\tau}$ is greatly reduced by optical illumination and is also a function of device active layer thickness and corresponding impurity flux density $Q_{Diff}$. Thus it is shown that the diffusion process shows great potential for improvement of optoelectronic devices in quantum efficiency and other performance areas.

• 자원환경지질
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• 제29권3호
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• pp.315-323
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• 1996

인회석 배수로가 1994년 9월 30일 미국 인디아나주 중서부에 위치한 Green Valley 폐탄광에 건설되었다. 현장설치의 일차적인 목적은 현장조건에서 산성수에 대한 인회석 배수로의 장기적인 처리능력을 평가하는 데 있다. 이 배수로는 실내실험결과에 따라 설계되었는데 연장 9m, 폭 3.3m, 심도 0.75m이며，95mm~30번 채 크기의 인회석광 (francolite)으로 채워져 있고 복구된 폐석더미로 부터 흘러나오는 산성수가 유입되게 되어 있다. 본 배수로는 폭우 및 실트의 퇴적으로 인한 손상을 막기 위해 석회석 자갈과 filter fabric으로 덮여져 있다. 본 배수로는 플로리다주의 인광석광산에서 채광된 50톤의 인회석으로 채워져 있다. 인회석은 산성수내의 첼 최대 4,200 mg/l, 알루미늄 최대 830 mg/l, 황산염 최대 13,430 mg/l를 제거하였다. 산도는 거의 일정하였으며 3.1에서 4.3까지 변화를 보였다. 배수로 하류에서 측정한 유출량은 3~4.5 l/m였다. 철 및 알루미늄 인산염 침전물은 노란색 및 흰색 부유성 입자인데 침전못에 계속적으로 퇴적되었다.