• Proceedings of the Korean Geotechical Society Conference
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• 1997.10a
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• pp.57-64
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• 1997

• Proceedings of the Korean Geotechical Society Conference
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• 2006.10a
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• pp.490-496
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• 2006

In order to design accurately plastic board drain (PBB) method, it is important to determine the equivalent circle of PBD. In this paper, a series of numerical analyses on soft ground improved by PBD were carried out, in order to investigate the resonable equivalent circle of PBD considering consolidation behavior of improved soft ground by PBD. The applicability of numerical analyses, in which an elasto-viscoplastic three-dimensional consolidation finite element method was applied, could be confirmed comparing with results of a series of model tests on consolidation behaviors of soft ground improved by PBD. And, through the results of the numerical analyses, consolidation behaviors of soft ground during consolidation was elucidated, together with the equivalent circle of PBD considering consolidation behaviors.

• JSTS:Journal of Semiconductor Technology and Science
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• v.17 no.1
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• pp.94-100
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• 2017

Stress drain bias dependent current model is proposed for sub-70-nm p-channel metal-oxide semiconductor field-effect transistors (pMOSFETs) under drain-avalanche-hot-carrier (DAHC-) mechanism. The proposed model describes the both on-current and off-current degradation by using two device parameters: channel length variation (${\Delta}L_{ch}$) and threshold voltage shift (${\Delta}V_{th}$). Also, it is a simple and effective model of predicting reliable circuit operation and standby power consumption.

• JSTS:Journal of Semiconductor Technology and Science
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• v.13 no.4
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• pp.331-341
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• 2013

In the present work, the effect of the gate-to-drain capacitance ($C_{gd}$) on the noise performance of a symmetric tied-gate $In_{0.52}Al_{0.48}As/In_{0.53}Ga_{0.47}As$ double-gate HEMT is studied using an accurate charge control based approach. An analytical expression for the gate-to-drain capacitance is obtained. In terms of the intrinsic noise sources and the admittance parameters ($Y_{11}$ and $Y_{21}$ which are obtained incorporating the effect of $C_{gd}$), the various noise performance parameters including the Minimum noise figure and the Minimum Noise Temperature are evaluated. The inclusion of gate-to-drain capacitance is observed to cause significant reduction in the Minimum Noise figure and Minimum Noise Temperature especially at low values of drain voltage, thereby, predicting better noise performance for the device.

• Journal of the Korean Society of Marine Environment & Safety
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• v.21 no.3
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• pp.303-308
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• 2015

Compressed air has many uses on board ship, ranging from diesel engine starting to the cleaning of machinery during maintenance. In an effort to enhance the performance of the marine compressed air system, this work studied a way to reduce condensation from the air compressor via experiments. Especially more condensation is produced when the temperature at compressor outlets and the humidity of the air are higher. so in the research, drain production change has been observed by additionally installing the cooling fan on the suction portion of the air to air compressor and this is the method for reducing the compressed air drain that has passed through the compressor. For the result, it was verified that when the cooling fan was used, less drain was made where per hour it was 500.9ml of drain and the measured result after installing the cooling fan was that less drain was made. Other additional and various researches are needed including experiments like silica gel passing through the suction portion afterwards.

• Proceedings of the Korean Geotechical Society Conference
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• 2000.03b
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• pp.685-692
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• 2000

Vertical drain used improvement soft clay is made of not only decreasing construction time but also increasing the ground strength during some decades. As, it is applied to improvement soft clay with vertical drain, it is designed by the result that is caused by oedemeter test ignored anisotropic of the ground related to consolidation conditions. When we are expected consolidation conditions, the most important factors is soil of compaction and water permeability. Above all, anisotropic of the ground permeability show the results which differ between vertical and radial drainage. Recently, We study for radial consolidation coefficient and permeability coefficient that utilized Rowe Cell Consolidation and permeability tester but, it dont use well because of not only a supply lack also difficulty of test. The paper experimented with searching anisotropic of the ground so there are Rowe Cell test, standard consolidation tester and modified standard consolidation test that have pohang's soft clay ground. Therefore, we find anisotropic of the ground and a tester of easy use more than before. We made a comparison test result between the devised tester and Rowe Cell tester, Also, we learned average degree of consolidation for partial penetrating vertical drains. We were found relations as effective stress-void and effective stress-permeability coefficient through those tests.

• Proceedings of the Korean Geotechical Society Conference
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• 2008.03a
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• pp.293-299
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• 2008

If a conventional type of Plastic Board Drain (PBD) is installed to the deep clay deposit, it is subjected to a high lateral earth pressure. a flow channel of PBD may be reduced by the collapse of cores and clogged by the intrusion of filter into the space between cores which are made by lateral pressure. It could decrease the ability of initial discharge capacity and the reliability of long term discharge capacity. A cylindrical plastic board drain (C-PBD) considered in this study consists of cylindrical core and several supports so that it can prevent the reduction of area of flow channel from the higher lateral earth pressure effectively. The discharge capacity of C-PBD was compared to that of a conventional PBD through performing experiments using the composite discharge capacity apparatus which can consider in-situ condition such as penetration of drains, ground settlement and discharge capacity. As a result, C-PBD showed much better performance than PBD in the ability of discharge. It was observed that the C-PBD was folded whereas the conventional PBD was folded after the experiment.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.48 no.10
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• pp.62-66
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• 2011

In this study, a new RF method to extract the drain-source voltage Vds-dependent gate-bulk capacitance of deep-submicron MOSFETs is developed by determining Vds-independent gate-source overlap capacitance using measured S-parameters. The accuracy of extraction method is verified by observing good agreements between the measured and modeled S-parameters. The lateral channel doping profile in the drain region is experimentally measured using a Vds-dependent curve of the overlap and depletion length obtained from the extracted data.

• JSTS:Journal of Semiconductor Technology and Science
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• v.17 no.2
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• pp.239-244
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• 2017

We experimentally investigate the physical mechanism for asymmetrical degradation in amorphous indium-gallium-zinc oxide (a-IGZO) thin-film transistors (TFTs) under simultaneous gate and drain bias stresses. The transfer curves exhibit an asymmetrical negative shift after the application of gate-to-source ($V_{GS}$) and drain-to-source ($V_{DS}$) bias stresses of ($V_{GS}=24V$, $V_{DS}=15.9V$) and ($V_{GS}=22V$, $V_{DS}=20V$), but the asymmetrical degradation is more significant after the bias stress ($V_{GS}$, $V_{DS}$) of (22 V, 20 V) nevertheless the vertical electric field at the source is higher under the bias stress ($V_{GS}$, $V_{DS}$) of (24 V, 15.9 V) than (22 V, 20 V). By using the modified external load resistance method, we extract the source contact resistance ($R_S$) and the voltage drop at $R_S$ ($V_{S,\;drop}$) in the fabricated a-IGZO TFT under both bias stresses. A significantly higher RS and $V_{S,\;drop}$ are extracted under the bias stress ($V_{GS}$, $V_{DS}$) of (22 V, 20V) than (24 V, 15.9 V), which implies that the high horizontal electric field across the source contact due to the large voltage drop at the reverse biased Schottky junction is the dominant physical mechanism causing the asymmetrical degradation of a-IGZO TFTs under simultaneous gate and drain bias stresses.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.51 no.3
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• pp.134-140
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• 2002

Deep submicron NMOSFETs with elevated source/drain can be fabricated using self-aligned selective epitaxial growth(SEG) of silicon for enhanced device characteristics with shallow junction compared to conventional MOSFETs. Shallow junctions, especially with the heartily-doped S/D residing in the elevated layer, give hotter immunity to Yt roll off, drain-induced-barrier-lowering (DIBL), subthreshold swing (SS), punch-through, and hot carrier effects. In this paper, the characteristics of both deep submicron elevated source/drain NMOSFETs and conventional NMOSFETs were investigated by using TSUPREM-4 and MEDICI simulators, and then the results were compared. It was observed from the simulation results that deep submicron elevated S/D NMOSFETs having shallower junction depth resulted in reduced short channel effects, such as DIBL, SS, and hot carrier effects than conventional NMOSFETs. The saturation current, Idsat, of the elevated S/D NMOSFETs was higher than conventional NMOSFETs with identical device dimensions due to smaller sheet resistance in source/drain regions. However, the gate-to-drain capacitance increased in the elevated S/D MOSFETs compared with the conventional NMOSFETs because of increasing overlap area. Therefore, it is concluded that elevated S/D MOSFETs may result in better device characteristics including current drivability than conventional NMOSFETs, but there exists trade-off between device characteristics and fate-to-drain capacitance.