• Title/Summary/Keyword: channel resistance

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Cooling effect of an electronic module with a variation of the inlet air temperature (유입공기의 온도변화가 전자모듈의 냉각에 미치는 영향)

  • 이진호;조성훈
    • Journal of the Korea Institute of Military Science and Technology
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    • v.4 no.1
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    • pp.264-273
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    • 2001
  • The conjugate heat transfer from a protruding module in a horizontal channel with a variation of air temperature is experimentally investigated. It is an aim of this study is to estimate temperature difference between a module and air. This study is performed with a variation of parameters that are air temperatures($T_i,=25^{\circ}C{\sim}55^{\circ}C),$ thermal resistance($R_c=158 K/W),$ air velocities ( 4V_i=0.1$ m/s~l.5 m/s ), and input power (Q=3 W, 7 W ). The results show that as the thermal resistance increases, the effect of air temperatures are decreased. And input power was most effective parameter on the temperature difference between a module and air.

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An Experimental Study for Resistance Performance of Small Size Fishing Vessel (소형 연안어선의 저항성능에 관한 실험적 연구)

  • Jeong, Uh-Cheul;Park, Chan-Won;Kim, Do-Jung;Kim, Young-Jun;Matsui, S.
    • Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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    • 2002.05a
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    • pp.251-256
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    • 2002
  • Resistance performance of small size fishing vessel is experimentally investigated to find out the effect of fore-body shape and trim for the better hull form development. The tests are performed for four different cases in the high speed circulating water channel(CWC). Wave patterns are observed together to investigate the relation between the resistance performance and the wave characteristics.

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Hull Form Development of a Small-Size High-Speed Coastal Leisure Boat (연안용 소형 고속 레저선 선형개발)

  • 정우철;박제웅;정석호
    • Journal of Ocean Engineering and Technology
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    • v.18 no.1
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    • pp.80-84
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    • 2004
  • The initial hull form of a 3 G/T and 30 knots class coastal leisure boat is newly developed. The performances measured, resistance, trim and sinkage, are investigated in a high-speed, circulating water channel (CWC). The effect of a fin attached on the hull side is studied together. Wave patterns are observed to clarify the relationship between the resistance performance and the wave characteristics. It can be found that the fin plays a role of increasing the resistance performance above a certain velocity.

Hull Form Development of 32-ft Class Leisure Boat by Statistical Analysis of Actual Ships (실적선 통계분석을 이용한 32피트급 레저보트 선형개발)

  • Jeong, Uh-Cheul;Park, Je-Woong;Kim, Kyu-Sun
    • Journal of Ocean Engineering and Technology
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    • v.22 no.3
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    • pp.58-63
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    • 2008
  • A 32-ft class leisure boat was newly developed using statistical analysis of actual ships. Resistance performances were investigated by testing models in a high-speed circulating water channel, and with the CFD method. The effects of a trim tab and of a fin attached at the hull side were studied together. Wave patterns were observed to clarify the relationship between resistance performance and wave characteristics. It was found that a trim tab and a side fin play a role in increasing resistance performance within a certain velocity range.

Discovery of Performance Traits-Linked Microsatellite Markers in Channel Catfish (Ictalurus punctatus)

  • Kim, Soon-Hag
    • Journal of Aquaculture
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    • v.18 no.2
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    • pp.130-132
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    • 2005
  • Genomics research has two ultimate applied goals: to Isolate and clone genes of economic importance for bio-technology and gene-assisted selection (GAS), and to locate and use markers for marker-assisted selection (MAS) in selective breeding programs. To this end, we have identified linked markers for feed conversion efficiency growth rate, and disease resistance to enteric septicemia of catfish (ESC). Three microsatellite markers Ip266, Ip384, and Ip607 were identified to be linked to feed conversion efficiency. Similarly one marker each was identified to be linked to growth rate (Ip607) and disease resistance to ESC (Ip477). Ip607 marker linked to both growth rate and feed conversion efficiency, indicating that the QTL for both growth rate and feed conversion efficiency may either be the same or located in the same chromosomal region in the catfish genome. On phenotypic evaluation, certain traits such as growth rate can be accurately evaluated by body weight evaluation while other traits such as disease resistance can be quite complex. The linked DNA markers will be highly useful for MAS programs and for directing further efforts of genomic mapping for important quantitative traits.

A Study on the Extraction of Mobility Reduction Parameters in Short Channel n-MOSFETs at Room Temperature (상온에서 짧은 채널 n-MOSFET의 이동도 감쇠 변수 추추에 관한 연구)

  • 이명복;이정일;강광남
    • Journal of the Korean Institute of Telematics and Electronics
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    • v.26 no.9
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    • pp.1375-1380
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    • 1989
  • Mobility reduction parameters are extracted using a method based on the exploitatiion of Id-Vg and Gm-Vg characteristics of short channel n-MOSFETs in strong inversion region at room temperature. It is found that the reduction of the maximum field effect mobility, \ulcornerFE,max, with the channel length is due to i) the difference between the threshold voltage and the gate voltage which corresponds to the maximum transconductance, and ii) the channel length dependence of the mobility attenuation coefficient, \ulcorner The low field mobility, \ulcorner, is found to be independent of the channel length down to 0.25 \ulcorner ofeffective channel length. Also, the channel length reduction, -I, the mobility attenuation coefficient, \ulcorner the threshold voltage, Vt, and the source-drain resistance, Rsd, are determined from the Id-Vg and -gm-Vg characteristics n-MOSFETs.

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Performance Evaluation of Natural Jute Fiber Reinforced Recycled Coarse Aggregate Concrete Using Response Surface Method (반응표면 분석법을 이용한 천연마섬유보강 순환굵은골재 콘크리트의 성능 평가)

  • Jeon, Ji Hong;Kim, Hwang Hee;Kim, Chun Soo;Yoo, Sung Yeol;Park, Chan Gi
    • Journal of The Korean Society of Agricultural Engineers
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    • v.56 no.4
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    • pp.21-28
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    • 2014
  • In this study, evaluated ware the strength and durability of the vegetated water purification channel concrete to which recycled aggregates, hawang-toh and jute were applied. Box-Behnken method of response surface analysis in statistics was applied to the experimental design. Experimental variables are as follows, recycled coarse aggregates, hawang-toh, blast-furnace slag and jute fiber. In the experiment, conducted were the tests of compressive strength, chloride ion penetration, abrasion resistance and impact resistance the replacement rate effects of the recycled aggregates, blast-furnace slag and hwang-toh on the performance of vegetated water purification channel concrete were analyzed by using the response surface analysis method on the basis of the experimental results. In addition, an optimum mixing ratio of vegetated water purification channel concrete was determined by using the experimental results. The optimum mixing ratio was determined to be in 10.0% recycled coarse aggregates, 60.0% blast-furnace slag, 10.1% hwang-toh and 0.16% jute fiber. The compressive strength, chloride ion penetration, abrasion rate, and impact number of fracture test results of the optimum mixing ratio were 24.1 MPa, 999 coulombs, 10.30 g/mm3, and 20 number, respectively.

Developments of double skin composite walls using novel enhanced C-channel connectors

  • Yan, Jia-Bao;Chen, An-Zhen;Wang, Tao
    • Steel and Composite Structures
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    • v.33 no.6
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    • pp.877-889
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    • 2019
  • The developments of double skin composite (DSC) walls with novel enhanced C-channel connectors (DSCW-EC) were reported. Followed axial compression tests on prototype walls were carried to evaluate structural performances of this novel DSC composite structures. The testing program consists of five specimens and focused on the layout of the novel enhanced C-channel (EC) connectors, which include the web direction of C-channels, steel-faceplate thickness, vertical and horizontal spacing of C-channels. Crushing in concrete core and buckling of steel faceplate were two main observed failed modes from the compression tests. However, elastic or plastic buckling of the steel faceplate varies with designed parameters in different specimens. The influences of those investigated parameters on axial compressive behaviors of DSCW-ECs were analyzed and discussed. Recommendations on the layout of novel EC connectors were then given based on these test results and discussions. This paper also developed analytical models for predictions on ultimate compressive resistance of DSCW-ECs. Validation against the reported test results show that the developed theoretical models predict well the ultimate compressive resistance of DSCW-ECs.

A study on Improvement of sub 0.1$\mu\textrm{m}$VLSI CMOS device Ultra Thin Gate Oxide Quality Using Novel STI Structure (STI를 이용한 서브 0.1$\mu\textrm{m}$VLSI CMOS 소자에서의 초박막게이트산화막의 박막개선에 관한 연구)

  • 엄금용;오환술
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.13 no.9
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    • pp.729-734
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    • 2000
  • Recently, Very Large Scale Integrated (VLSI) circuit & deep-submicron bulk Complementary Metal Oxide Semiconductor(CMOS) devices require gate electrode materials such as metal-silicide, Titanium-silicide for gate oxides. Many previous authors have researched the improvement sub-micron gate oxide quality. However, few have reported on the electrical quality and reliability on the ultra thin gate oxide. In this paper, at first, I recommand a novel shallow trench isolation structure to suppress the corner metal-oxide semiconductor field-effect transistor(MOSFET) inherent to shallow trench isolation for sub 0.1${\mu}{\textrm}{m}$ gate oxide. Different from using normal LOCOS technology deep-submicron CMOS devices using novel Shallow Trench Isolation(STI) technology have a unique"inverse narrow-channel effects"-when the channel width of the devices is scaled down, their threshold voltage is shrunk instead of increased as for the contribution of the channel edge current to the total channel current as the channel width is reduced. Secondly, Titanium silicide process clarified that fluorine contamination caused by the gate sidewall etching inhibits the silicidation reaction and accelerates agglomeration. To overcome these problems, a novel Two-step Deposited silicide(TDS) process has been developed. The key point of this process is the deposition and subsequent removal of titanium before silicidation. Based on the research, It is found that novel STI structure by the SEM, in addition to thermally stable silicide process was achieved. We also obtained the decrease threshold voltage value of the channel edge. resulting in the better improvement of the narrow channel effect. low sheet resistance and stress, and high threshold voltage. Besides, sheet resistance and stress value, rms(root mean square) by AFM were observed. On the electrical characteristics, low leakage current and trap density at the Si/SiO$_2$were confirmed by the high threshold voltage sub 0.1${\mu}{\textrm}{m}$ gate oxide.

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