• EDISON SW 활용 경진대회 논문집
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• 제6회(2017년)
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• pp.424-427
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• 2017

This study investigated the effect of strain on hole mobility and hole effective mass in a p-channel rectangular nanowire with two-dimensional confinement. We obtained the valence energy band structure using the six-band k.p method and calculated the mobility and effective mass of the hole in the [100] direction taking the strain effect into account in the inversion region. The hole mobility of strained silicon was calculated using Kubo-Greenwood formalism. As a result, it showed good performance compared to relaxed silicon, but its magnitude was insignificant.

• Journal of Mechanical Science and Technology
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• 제14권3호
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• pp.350-357
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• 2000

Experiments were performed by using PF-5060 and water to investigate the influence of an aspect ratio of a horizontal rectangular channel on the cooling characteristics from an in-line $6{\times}1$ array of discrete heat sources which were flush mounted on the top wall of the channel. The experimental parameters were aspect ratio of rectangular channel, heat flux of simulated VLSI chip, and channel Reynolds number. The chip surface temperatures decreased with the aspect ratio at the first and sixth rows, and decreased more rapidly at a high heat flux than at a low heat flux. The measured friction factors at each aspect ratio for both water and PF-5060 gave a good agreement with the values predicted by the modified Blasius equation within ${\pm}7%$. The Nusselt number increased as the aspect ratio decreased, but the increasing rate of Nusselt number reduced as the aspect ratio decreased. A 5:1 rectangular channel yields the most efficient cooling performance when the heat transfer and pressure drop in the test section were considered simultaneously.

• 한국해양공학회지
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• 제25권4호
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• pp.23-27
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• 2011

This experimental study was performed to find rpms of the impeller and the surface flow accelerator to make a uniform velocity vertical distribution in the circular water channel. PIV technique was employed to measure the water velocity profiles into the water depth from the free surface. The number of instantaneous velocity profiles was decomposed into mean and turbulence velocity components, and the distribution of velocity fluctuation and turbulence intensity were computed for each experimental condition. From these results, the velocity uniformity was quantitatively determined to present the flow quality in the measuring section of the circular water channel. It has been shown that the proper operation of the surface flow accelerator would make the uniform velocity profiles and reduce the velocity fluctuation near the free surface.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2003년도 춘계종합학술대회
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• pp.629-632
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• 2003

This paper presents a way to maximize transmission efficiency and reception ability through transmission diversity technology, which can be adapted to wireless multimedia OFDM system. The presented method is a comparative analysis between a case where parameter $\alpha$for time average is 0.3, 1 with consideration of channel presumption with two types of rms delayed proliferation, which is 50nsec, 150nsec, for the performance analysis of STTC(Space-Time Trellis Code) using time-space ciphering method appropriate for MIMO channel, and performance in the case where presumed channel value from long training column section is applied to according frame in a single frame. The result showed that BER brought SNR improvement of 1.0dB in 10-3 when $\alpha$ was 0.3 than using only the long training column, and showed increase of general performance improvement for the sake of time average rather than the case without.

• 한국농공학회:학술대회논문집
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• 한국농공학회 2002년도 학술발표회 발표논문집
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• pp.157-160
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• 2002

This study was developed high-quality a large size precast channel structure using polymer concrete to improve quality of the product as well as to enhance construction quality. Practical precast channel structure design and manufacture procedure for the high polymer concrete were described in this paper. Precast PC represent the fastest growing segment of the polymer concrete industry. The fast curing, high strength, and low impermeability permit thin section and rapid reuse of moulds. Precast channel structure will carry out structural experiment and analysis.

• Journal of Advanced Marine Engineering and Technology
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• 제28권8호
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• pp.1195-1202
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• 2004

In this paper an experimental study was investigated for two-phase flow distribution in compact heat exchanger header. A test section was consisted of the horizontal bottom dividing header($\phi$: 5 mm, L: 80 mm) and 10 upward circular mini channels ($\phi$: 1.5 mm, L: 850 mm) using an acrylic tube. Three different types of tube intrusion depth were tested for the mass flux and inlet mass quality ranges of 50 - 200 kg/$m^2$s and 0.1 - 0.3, respectively. Air and water were used as the test fluids. The distribution of vapor and liquid is obtained by measurement of the total mass flow rate and the calculation of the quality. Two-phase flow pattern was observed, and pressure drop of each channel was measured. By adjusting the intrusion depth of each channel an uniform liquid flow distribution through the each channel was able to solve the mal-distribution problem.

• 한국수자원학회논문집
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• 제34권5호
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• pp.551-560
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• 2001

낙동강의 화원-교령교-현풍 수위관측소 구간에 대하여 수리학적 하도추적을 통하여 조도계수를 추정하였다. 세 관측소의 연속 수위자료와 하천 종횡단 측량자료만이 이에 사용되었다. 하도추적에 의해 계산된 유량자료로부터 수위-유량 관계식을 작성하였으며 이는 기존의 수위-유량 관계식보다 나은 결과를 보였다. 수위측정 오차가 유량계산에 미치는 영향에 대하여 분석하였으며, 측방유입류를 억제할 수 있도록 하도길이를 제한하는 방법도 제시하였다.

• ETRI Journal
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• 제28권5호
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• pp.545-554
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• 2006

A widely tunable multi-channel grating cavity laser is proposed and experimentally demonstrated. The device is implemented in Littman configuration with an echelle grating based on Rowland circle construction and realized by monolithically integrating all elements in an InP substrate. Lasing wavelength is selected by turning on an amplifier and the appropriate channel element in the array, and it is tuned by controlling light deflection electrically. The 6-channel device exhibits a tuning range of about 50 nm with a side mode suppression ratio of more than 30 dB. This is accomplished by adjusting the applied current of the dispersive element and phase control section.

• Journal of Advanced Marine Engineering and Technology
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• 제33권6호
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• pp.912-917
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• 2009

An experimental flow visualization study of the entrance section of channels formed with wavy plates was made. The experiments were conducted in a water channel and a laser illuminated particle tracking was used as the technique of flow visualization. The flow region that were found in the experiments are steady, unsteady and significantly-mixed flows. Instabilities of the flow first appear near the exit of the channel. As the Reynolds number increases, the flows are characterized by the appearance of flow separation and the growth of recirculation region.

• Water Engineering Research
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• 제3권3호
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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.