• International Journal of Naval Architecture and Ocean Engineering
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• 제8권2호
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• pp.169-176
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• 2016

In this paper, further research is carried out to investigate the resistance encountered by an icebreaking vessel travelling through level ice and channel ice at low speed range. The present paper focuses on experimental and calculated ice resistances by some empirical formulas in both level ice and channel ice. In order to achieve the research, extra model tests have been done in an ice basin. Based on the measurements from model test, it is found that there exists a relationship between ice resistance, minimum ice load, maximum ice load and the standard deviation of ice load for head on operation in level ice. In addition, both level ice resistance and channel ice resistance are calculated and compared with model test results.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2009년도 춘계학술대회 논문집
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• pp.63-64
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• 2009

The TFTs have been fabricated with 3 different geometry SID electrodes which have the same channel W/L ratio (W/L = 5) due to constant channel resistance, The 3 samples have different channel widths (350, 150, and $25\;{\mu}m$) and channel lengths (70, 30, and $5\;{\mu}m$) by fixed channel W/L ratio simultaneously on one chip for reliable comparisons. Resultant on-current and field effect mobility are proportional to the channel width, while the subthreshold swing is inversely proportional to the channel width mainly due to the change of contact resistance. These results show that the contact resistance strongly affects the device performances and should be considered in the applications.

• 설비공학논문집
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• 제13권5호
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• pp.348-355
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• 2001

The coupled conduction and convection heat transfer from a protruding heated module in a horizontal channel with a variation of channel height is experimentally investigated. The input power to the module is 3, 7W and thermal resistance of module support is 0.06 , 1.03 and 158K/W. the Reynolds number ranged from 350 to 4500 corresponding to the inlet velocity(0.4~1.3 m/s) and channel height(11~35 mm). The results were obtained that the decrease of thermal resistance of module support reduces the module temperature by redistributing the heat flux and the overall thermal resistance of the module. In the study the effect of channel height is very significant in the adiabatic condition, but negligible in the conjugate condition. Finally, correlations for Nusselt number and $Q_B$/Q with a variation of Reynolds number were developed respectively.

• 한국전기전자재료학회논문지
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• 제22권9호
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• pp.747-750
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• 2009

The TFTs have been fabricated with 3 different geometry SID electrodes which have the same channel W/L ratio (W/L = 5) due to constant channel resistance, The 3 samples have different channel widths (350, 150, and 25 ${\mu}m$) and channel lengths (70, 30, and 5 ${\mu}m$) by fixed channel W/L ratio simultaneously on one chip for reliable comparisons. Resultant on-current and field effect mobility are proportional to the channel width, while the subthreshold swing is inversely proportional to the channel width mainly due to the change of contact resistance. These results show that the contact resistance strongly affects the device performances and should be considered in the applications.

• 한국기계가공학회지
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• 제20권11호
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• pp.121-126
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• 2021

In this study, the effect of thermal contact resistance between pin-channel tubes on the heat transfer characteristics was analytically examined around the channel tubes with the pins attached to two consecutive arranged channel pipes. The numerical results showed that the heat transfer coefficient decreased geometrically as the thermal contact resistance increased, and the corresponding temperature change on the contact surface increased as the thermal contact resistance increased. The thinner the pin, the more pronounced the geometric drop in the heat transfer coefficient. It was confirmed that the higher the height of the pin, the higher was the heat transfer coefficient, however, the greater the size of the thermal contact resistance, the smaller was the heat transfer coefficient. It was found that the temperature change in the inner wall of the channel tube did not significantly affect the heat transfer characteristics owing to the thermal contact resistance. Furthermore, the velocity of air at the entrance of the channel tube was proportional to the heat transfer coefficient due to a decrease in the convective heat resistance corresponding to an increase in the flow rate.

• 한국전기전자재료학회논문지
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• 제32권4호
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• pp.272-275
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• 2019

We investigated the electrical characteristics of amorphous silicon-zinc-tin-oxide (a-SZTO) thin films deposited by RF-magnetron sputtering at room temperature depending on the deposition time. We fabricated a thin film transistor (TFT) with a bottom gate structure and various channel thicknesses. With increasing channel thickness, the threshold voltage shifted negatively from -0.44 V to -2.18 V, the on current ($I_{on}$) and field effect mobility (${\mu}_{FE}$) increased because of increasing carrier concentration. The a-SZTO film was fabricated and analyzed in terms of the contact resistance and channel resistance. In this study, the transmission line method (TLM) was adopted and investigated. With increasing channel thickness, the contact resistance and sheet resistance both decreased.

• 대한기계학회논문집B
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• 제32권10호
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• pp.776-783
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• 2008

The object of this paper is to study on the thermal performance of a micro channel water block for computer CPU cooling. The effects of liquid flow rate, micro channel width and height on the thermal performances of water block are investigated experimentally. The water block was fabricated Al and machined with a micro milling. The water block consisted of rectangular micro channels 0.5 to 0.9 mm width and 1.5 to 4.5 mm height. The experiments were conducted using deionized water, over a liquid flow rate ranging from 0.2 to 2.0 kg/min. The base temperature and thermal resistance decrease with increasing of liquid flow rate. The increase of a channel height is more effective on the thermal resistance than the decrease of a channel width. At the flow rate of 0.7 kg/min, input power of 100 W, the base temperature and thermal resistance of sample 6 is $33^{\circ}C$ and $0.13\;^{\circ}C/W$ respectively.

• 대한조선학회논문집
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• 제55권1호
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• pp.22-27
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• 2018

Ships strengthened for navigation in ice encounter level ice, ice ridge and broken ice fields. Thus, the ship resistance in ice is a very critical concern to the designers of ice-going vessels. The objective of this study is to understand the physical aspects of ship performance in ice and to investigate the characteristics of the ship resistance in broken ice channels. In particular, this study identifies the ship resistance in ice associated with the broken ice channel width and the size of broken ice pieces. Model testings of towed-resistance condition in broken ice channels with three ship speeds were conducted in KRISO ice model basin. The influence of the ship resistance characteristics in broken ice channels for channel width and size of broken ice pieces was analyzed.

• 한국표면공학회지
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• 제49권2호
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• pp.152-158
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• 2016

We investigated the effect of capacitively coupled Ar plasma treatment on contact resistance ($R_c$) and channel sheet resistance ($R_{sh}$) of graphene field effect transistors (FETs), by varying their channel length in the wide range from 200 nm to $50{\mu}m$ which formed the transfer length method (TLM) patterns. When the Ar plasma treatment was performed on the long channel ($10{\sim}50{\mu}m$) graphene FETs for 20 s, $R_c$ decreased from 2.4 to $1.15k{\Omega}{\cdot}{\mu}m$. It is understood that this improvement in $R_c$ is attributed to the formation of $sp^3$ bonds and dangling bonds by the plasma. However, when the channel length of the FETs decreased down to 200 nm, the drain current ($I_d$) decreased upon the plasma treatment because of the significant increase of channel $R_{sh}$ which was attributed to the atomic structural disorder induced by the plasma across the transfer length at the edge of the channel region. This study suggests a practical guideline to reduce $R_c$ using various plasma treatments for the $R_c$ sensitive graphene and other 2D material devices, where $R_c$ is traded off with $R_{sh}$.

• 전자공학회논문지
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• 제54권5호
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• pp.11-16
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• 2017

RF MOSFET에서 관찰된 입력 저항의 주파수 종속 특성이 단순화된 입력 등가회로로부터 유도된 pole과 zero 주파수 수식을 사용하여 자세히 분석되었다. 이러한 이론적 분석을 사용하여 저주파에서 입력저항의 감소현상이 포화영역에서 소스와 pinch-off 영역 사이의 채널저항으로부터 발생되는 것을 발견하였다. 이와 같이 저주파에서 입력저항이 감소하는 채널 저항 효과는 채널저항을 변화시키면서 소신호 등가회로 모델링을 수행하여 물리적으로 입증되었다.