• Journal of the Society of Naval Architects of Korea
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• v.40 no.4
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• pp.22-29
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• 2003

New high-speed depressurized circulating water channel was designed by using the CFD code. Flow in the channel has free surface and pressure in the test section can be depressed. In this study, Flow separation and bubble occurrence were considered in designing the contraction nozzle shape for better flow uniformity Tn the test section. To supplement velocity defect due to the free surface, nozzle injection system more effective in high-speed flow was installed instead of drum system. Necessary power and injection techniques were proposed. And guide vane arrangement was analyzed to reduce the flow resistance and keep quiet free surface from ´surging´. Wave absorber was devised to reduce the wave resistance and to prevent the entrainment of air to the diffuser.

• ETRI Journal
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• v.28 no.2
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• pp.253-256
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• 2006

We propose a novel power metal oxide semiconductor field effect transistor (MOSFET) employing a strained-Si channel structure to improve the current drivability and on-resistance characteristic of the high-voltage MOSFET. A 20 nm thick strained-Si low field channel NMOSFET with a $0.75\;{\mu}m$ thick $Si_{0.8}Ge_{0.2}$ buffer layer improved the drive current by 20% with a 25% reduction in on-resistance compared with a conventional Si channel high-voltage NMOSFET, while suppressing the breakdown voltage and subthreshold slope characteristic degradation by 6% and 8%, respectively. Also, the strained-Si high-voltage NMOSFET improved the transconductance by 28% and 52% at the linear and saturation regimes.

• Proceedings of the KSME Conference
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• 2008.11b
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• pp.2652-2657
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• 2008

An analytical study was carried out on the flow resistance of tree-shaped channel flow architectures, based on the principle of the constructal law of evolutionary increase of flow access through the generation of better flowing configurations with two diameters in the square domain. Two types of tree-shaped configurations are optimized. The minimized global flow resistance decreases definitely as the system size, N, increases. And the best channel configurations among the first construct and second construct as a result of regarding pressure drop was selected. We also show that the freedom to morph the design and to increase its performance can be enhanced by using tree-tree configurations with $2^{nd}$ construct when N is greater than 18.

• Water Engineering Research
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• v.3 no.3
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• pp.177-193
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• 2002

Experiments were conducted in an initially straight laboratory alluvial channel to investigate channel meandering characteristics. The experimental observations revealed an empirical relation between three types of tortuosity ratios used for describing meandering characteristics. Furthermore, the Strauhal number was found to be higher for bed material with greater resistance to erosion than with lower resistance to erosion. The meandering characteristics were also investigated using the concept of buckling employed in solid mechanics and the concept of siphoning of fluid mechanics. The buckling of flow, attributable to the flow nonuniformity across the channel cross-section, was found to follow the same pattern as did meandering observed experimentally. The processes of expansion of meanders and cut-off can be explained using the concept of siphoning. The results of expanding meander planforms observed in four experimental tests supported the viability of these concepts.

• Proceedings of the KIEE Conference
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• 1996.11a
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• pp.261-263
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• 1996

The study on the development of one-channel gas sensor using the quartz crystal analyzer were attempted. The adsorption and desorption behavior of organic gases were investigated using the resonant frequency and resistance method of quartz crystal. The sensitive materials were deposited on the quartz crystal analyzer(QCA) by using Langmuir-Blodgett method. To investigate the response characteristics of organic vapours and response mechanism, resonant frequency-resonant resistance (F-R) diagram was used. In our experimental results, the response mechanism between sensitive LB film and organic vapours was obtained using F-R diagram. And the position of each organic vapour were different as to the kind and injection amount. Thus F-R diagram can be applied to one-channel gas sensor using the QCA and useful to analyze the response mechanism between organic vspours and sensitive LB films.

• Transactions on Electrical and Electronic Materials
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• v.17 no.1
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• pp.46-49
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• 2016

A thin film transistor (TFT) has been fabricated using the amorphous 0.5 wt% Si doped zinc-tin-oxide (a-0.5 SZTO) with different electrodes made of either aluminium (Al) or titanium/aluminium(Ti/Al). Contact resistance and total channel resistance of a-0.5SZTO TFTs have been investigated and compared using the transmission line method (TLM). We measured the total resistance of 1.0×10² Ω/cm using Ti/Al electrodes. This result is due to Ti, which is a material known for its adhesion layer. We found that the Ti/Al electrode showed better contact characteristics between the channel and electrodes compared with that made of Al only. The former showed a less contact and total resistance. We achieved high performance of the TFTs characteristic, such as Vth of 2.6 V, field effect mobility of 20.1 cm² V⁻¹s⁻¹, S.S of 0.9 Vdecade⁻¹, and on/off current ratio of 9.7×10⁶ A. It was demonstrated that the Ti/Al electrodes improved performance of TFTs due to enhanced contact resistance.

• Water Engineering Research
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• v.6 no.3
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• pp.101-112
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• 2005

This paper presents the state of the art of the CFD applications to vegetated open-channel flows. First, important aspects of the physics of vegetated flows found through the laboratory experiments are briefly reviewed. Then, previous CFD applications to one-dimensional vertical structure, partly-vegetated flows, compound open-channel flows with floodplain vegetation, and fully three-dimensional numerical simulations are reviewed. Finally, topics for further researches such as relationship between the resistance and flexural rigidity, additional drag due to foliages, and melting the experience of CFD with the depth-averaged modeling, are suggested.

• Journal of the Semiconductor & Display Technology
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• v.2 no.2
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• pp.17-20
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• 2003

The current drive in an MOSFET is limited by the intrinsic channel resistance. All the other parasitic elements in a device structure playa significant role and degrade the device performance. These other resistances need to be less than 10%-20% of the channel resistance. To achieve the requirements, we should investigate a methodology of separation and quantification of those resistances. In this paper, we developed the extraction method of resistances using calibrated TCAD simulation. The resistance of the extension region is also partially determined by the formation of a surface accumulation region that forms under the gate in the tail region of the extension profile.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2000.10a
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• pp.261-264
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• 2000

Two hull forms of 2, 500 TEU Container Vessel, designed by Daedong Shipbuilding CO., LTD. were tested at the Circulating Water Channel of Chosun University for the evaluation of resistance performance. The test results of resistance, wave profile measurement and trim-sinkage measurement are compared in the form of diagrams and figures, and the results are discussed. A conclusion is drawn that the performance of modified form (model number : CU-201F2A2) is improved about 8% resistance performance at the design speed compare with original form (model number : CU-201F1A1).

• Proceedings of the IEEK Conference
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• 2006.06a
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• pp.481-482
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• 2006

We fabricated pentacene organic thin film transistor with good uniformity. And we extracted contact resistance in organic thin film transistors from the plot of the inverse of drain current versus channel length by extrapolating the curve to a channel length of zero, and multiplying by drain-source voltage. Extracted contact resistance is about $70K{\Omega}$ at gate-drain voltage of -20 V