• Title/Summary/Keyword: the independent film

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Non-absorbable Gas Effects on Heat and Mass Transfer in Falling Film Absorption

  • Kim, Byongjoo;Lee, Chunkyu
    • Journal of Mechanical Science and Technology
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    • v.17 no.4
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    • pp.581-589
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    • 2003
  • Film absorption involves simultaneous heat and mass transfer in the gas-liquid system. While the non-absorbable gas does not participate directly In the absorption process. its pretence does affect the overall heat and mass transfer. An experimental study was performed to investigate the heat and mass transfer characteristics of LiBr-H$_2$O solution flow ing over 6-row horizontal tubes with the water vapor absorption in the pretence of non-absorbable gases. The volumetric concentration of non-absorbable gas, air, was varied from 0.17 to 10.0%. The combined effects of the solution flow rate and its concentration on the heat and mass transfer coefficients were also examined. The presence of 2% volumetric concentration of air resulted in a 25% reduction in the Nusselt number and 41% reduction in the Sherwood number Optimum film Reynolds number was found to exist at which the heat and mass transfer reach their maximum value independent of air contents. Reduced Nusselt and Sherwood numbers. defined as the ratio of Nusselt and Sherwood numbers at given non-absorbable gas content to that with pure water vapor, were correlated to account for the reduction in the heat and mass transfer due to non-absorbable gases in a falling film absorption process.

Multi-scale Analysis of Thin Film considering Surface effects (표면효과를 고려한 박막구조의 멀티스케일 해석)

  • Choi, Jin-Bok;Jung, Kwang-Sub;Cho, Maeng-Hyo
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 2007.04a
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    • pp.427-432
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    • 2007
  • In general, the response of bulk material is independent of its size when it comes to considering classical elasticity theory. Because the surface to bulk ratio of the large solids is very small, the influence of surface can be negligible. But the surface effect plays important role as the surface to bulk ratio becomes larger, that is, the contribution of the surface effect must be considered in nano-size elements such as thin film or beam structure. Molecular dynamics computation has been a conventional way to analyze these ultra-thin structures but this method is limited to simulate on the order of $10^6-10^8$ atoms for a few nanoseconds, and besides, very time consuming. Analysis of structures in submicro to micro range(thin-film, wire etc.) is difficult with classical molecular dynamics due to the restriction of computing resources and time. Therefore, in this paper, the continuum-based method is considered to simulate the overall physical and mechanical properties of the structures in nano-scale, especially, for the thin-film.

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Functional Analysis of Music Used in Film

Experimental Investigation on the Inlet Pressure Build-Up at the Entrance of a Large Tilting Pad Journal Bearing (대형 틸팅패드 저어널베어링의 패드 입구에서 발생하는 선단압력에 관한 실험적 연구)

  • 하현천;김경우;김영춘;김호종
    • Tribology and Lubricants
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    • v.9 no.2
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    • pp.22-28
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    • 1993
  • The experimental investigation on the inlet pressure of a large tilting pad journal bearing is studied. The continuous distribution of the film pressure and film thickness are measured along with the shaft speed and bearing load for various flow rates. Considerably large inlet pressure is observed at the entrance of each pad, especially lower pads. The inlet pressure increases with the increase of shaft speed as well as bearing load, but it is almost independent on the folw rate and the oil supply temperature. Because of the inlet pressure, the upper pads always keep up slight wedge film shape which are almost parallel to the journal surface, and spragging is not observed in the upper pads with no preload.

Nanoindentation experiments on some thin films on silicon (Nanoindentation 방법에 의한 박막의 경도 및 탄성계수 측정)

  • 한준희
    • Journal of the Korean Ceramic Society
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    • v.37 no.6
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    • pp.596-603
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    • 2000
  • The hardness and elastic modulus of three bulk materials are computed from the load and displacement data which are measured during basic nanoindentation test and compared with values determined by independent means to assess the accuracy of the method. The results show that with this technique, modulus and hardness and elastic modulus profile through depth of silicon nitride and silicon oxynitride films. The results show that for silicon nitride film deposited on silicon, hardness and elastic modulus increase as the volume ratio of NH3 : SiH4, which had been used for deposition, increases up to 20.0; and for silicon oxynitride film on silicon, the hardness and elastic modulus profile changes distinctly as the relative amount of oxygen in deposition gas mixture changes.

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The Space Evaluation in Living Rooms with Slide Film (슬라이드 실험을 통한 거실공간평가)

  • 임소연
    • Journal of the Korean housing association
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    • v.8 no.1
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    • pp.37-48
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    • 1997
  • The purpose of this study supply data that can make a living room a more comfortable space by using a plan of furniture usage, that is to say more affective to human's mental and physical character. For this purpose made experiment with slide film on 39 representative descriptions. The object of this research was female university students and to analyze the data. factor analysis. One-way ANOVA and scheffe-test were used by running SPSS PC+ program. The major results are as follows. In experiment with slide film for grasping spatial effect and evaluation on the 39 representative descriptions, three dimensions(clearness. openness. variety) extracted as the result of factor analysis. Especially the result of this study - sizes of space put independent valuables and each demotion put dependent valuables - shows differences according to space’ size.

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A Study on Calibration of Heat Flux Sensor by using Convective Heat Transfer (대류방식을 이용한 열유속센서의 검정에 관한 연구)

  • Yang, Hoon-Cheul;Song, Chul-Hwa;Kim, Moo-Hwan
    • Proceedings of the KSME Conference
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    • 2004.04a
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    • pp.1358-1363
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    • 2004
  • The objective of this work is to propose calibration facility in which a thin film type heat flux sensor can be calibrated under convective flow condition by using a small wind tunnel with the constant temperature plate condition. A small wind tunnel has been built to produce a boundary layer shear flow above a constant temperature copper plate. 12-independent copper blocks, thin film heaters, insulators and temperature controllers were used to keep the temperature of flat plate constant at a specified temperature. Three commercial thin film-type heat flux sensors were tested. Convective calibrations of these gages were performed over the available heat flux range of $1.4{\sim}2.5kW/m^2$. The uncertainty in the heat flux measurements in the convective-type heat flux calibration facility was ${\pm}2.07%$. Non-dimensional sensitivity is proposed to compare the sensitivity calibrated by manufacturer and that of experiment conducted in this study.

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Electrical Properties of SCT Ceramic Thin Film (SCT 세라믹 박막의 전기적 특성)

  • 김원종;조춘남;김진사;소병문;송민종;박건호;김충혁;이준웅
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2000.07a
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    • pp.440-443
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    • 2000
  • The (Sr$_{1-x}$ Ca$_{x}$) thin films ale deposited OR Pt-Coated electrode(Pt/TiN/SiO$_2$/Si) using RF sputtering method with substitutional contents of Ca. The maximum grain of thin films is obtained at SCT15 thin film. The dielectric constant was increased with increasing the substitutional contents of Ca, while it was decreased if the substitutional contents of Ca exceeded over 15[mol%]. The temperature properties of the dielectric loss have a stable value within 2% independent of the substitutional contents of Ca.Ca.

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Hysteresis Characteristics in Low Temperature Poly-Si Thin Film Transistors

  • Chung, Hoon-Ju;Kim, Dae-Hwan;Kim, Byeong-Koo
    • Journal of Information Display
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    • v.6 no.4
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    • pp.6-10
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    • 2005
  • The dependence of hysteresis characteristics in low temperature poly-Si (LTPS) thin film transistors (TFTs) on the gate-source voltage (Vgs) or the drain-source voltage (Vds) bias is investigated and discussed. The hysteresis levels in both p-type and n-type LTPS TFTs are independent of Vds bias but increase as the sweep range of Vgs increases. It has been found that the hysteresis in both p-type and n-type LTPS TFTs originated from charge trapping and de-trapping in the channel region rather than at the source/drain edges.

Highly Miniaturized and Performed UWB Bandpass Filter Embedded into PCB with SrTiO3 Composite Layer

  • Cheon, Seong-Jong;Park, Jun-Hwan;Park, Jae-Yeong
    • Journal of Electrical Engineering and Technology
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    • v.7 no.4
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    • pp.582-588
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    • 2012
  • In this paper, a highly miniaturized and performed UWB bandpass filter has been newly designed and implemented by embedding all the passive elements into a multi-layered PCB substrate with high dielectric $SrTiO_3$ composite film for 3.1 - 4.75 GHz compact UWB system applications. The high dielectric composite film was utilized to increase the capacitance densities and quality factors of capacitors embedded into the PCB. In order to reduce the size of the filter and avoid parasitic EM coupling between the embedded filter circuit elements, it was designed by using a $3^{rd}$ order Chebyshev circuit topology and a capacitive coupled transformation technology. Independent transmission zeros were also applied for improving the attenuation of the filter at the desired stopbands. The measured insertion and return losses in the passband were better than 1.68 and 12 dB, with a minimum value of 0.78 dB. The transmission zeros of the measured response were occurred at 2.2 and 5.15 GHz resulting in excellent suppressions of 31 and 20 dB at WLAN bands of 2.4 and 5.15 GHz, respectively. The size of the fabricated bandpass filter was $2.9{\times}2.8{\times}0.55(H)mm^3$.